This section specifies the basic kinds of things each science uses to sort its domain: not individual entities or their properties, but the types they fall into. These are its primitive ontological bins—substances vs processes, states vs events, fields vs particles, agents vs institutions, signals vs meanings, structures vs relations, etc. The Categories row forces each field to say how its world is carved up at the most fundamental level: what counts as a system, what counts as a state, what counts as a process, what counts as a structure, and what counts as a relation or interaction. Once these categories are fixed, every entity and property in the domain has to enter explanation through one of these types, which locks in how the field can generalize, compare cases, and build higher-level classifications.

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Science Analysis Template

Below are the results of cycles 1 & 2 of The Science Project

Unified Ontological Two-Axis System for Scientific Domains

Every scientific discipline divides the world in two fundamental ways, even if it never says so explicitly.

First, each science distinguishes what kinds of things exist in its domain: particles, fields, organisms, tissues, markets, institutions, networks, signals, algorithms, proofs, ecosystems, populations, roles, regimes, and models. These are not random lists. They fall into a small and universal set of ontological types that recur across all fields. A “particle” in physics, a “cell type” in biology, a “firm” in economics, and a “node” in graph theory all play structurally similar roles in their respective sciences—they are carriers of properties, participants in processes, elements of structures, or components in systems. Sciences differ in vocabulary, but they rely on the same underlying kinds of entities to build their explanations.

Second, each science classifies those things along key conceptual dimensions that determine how the world behaves: micro vs macro, discrete vs continuous, equilibrium vs non-equilibrium, deterministic vs stochastic, linear vs nonlinear, open vs closed, local vs global, classical vs quantum. These dimensions are not domain-specific—they are universal. They tell us whether a phenomenon is stable or unstable, simple or chaotic, predictable or probabilistic, isolated or interacting, granular or flowing. Every model, theory, and method implicitly chooses where its objects sit along these axes.

The Unified Ontological Two-Axis System makes these two patterns explicit and formal.
It states that every scientific entity—no matter the field—can be located at the intersection of:

• an ontological type (what kind of thing it is), and
• a descriptive class (the behavioral regime it occupies).

This produces a coherent coordinate system that reveals deep structural similarities across sciences that otherwise appear unrelated. It shows, for example, that a “turbulent flow regime,” a “boom–bust economic cycle,” a “neural firing mode,” and a “nonlinear PDE solution family” all belong to the same conceptual slot, even though they arise in different domains. Likewise, a “market participant,” a “cell receptor,” a “topological defect,” and a “syntactic subject” all instantiate the same ontological role type in their respective systems.

By exposing the shared architecture beneath scientific classification, the system allows you to reorganize the sciences not by subject matter but by the structural logic of their explanations. It unifies natural, social, and formal sciences into a single ontological grid that makes explicit what has always been implicit in scientific reasoning.

Ontological Type Axes

What kind of thing is this?

Every scientific domain—physics, chemistry, biology, linguistics, economics, sociology, mathematics—implicitly sorts its entities into a small set of ontological types. These types are not tied to any one field. They recur everywhere because they represent the fundamental ways phenomena can exist or appear inside a scientific explanation.

An entity may carry properties, occupy a state, participate in processes, form structures, belong to systems, exhibit characteristic regimes, play roles, or exist as a representation or model. These are the building blocks of all scientific theory.

The purpose of Axis A is to formalize these categories so that every scientific object—no matter its discipline—can be assigned a clear ontological identity. When this is done, the diversity of scientific vocabulary collapses into a coherent architecture. What appears as unrelated domain jargon is actually the same underlying ontology repeated with different surface labels.

This axis answers the fundamental question:

“What kind of entity is this in the structure of scientific explanation?”

Below is the complete set of universal ontological types.

SAT – Domain – Categories – Ontological Type Axes

Ontological Type	Core Meaning	Examples Across Sciences
Carrier / Substance	A “thing” that holds properties and can be measured or interacted with. The basic unit that other types operate on.	particle, molecule, rock, cell, organ, agent, firm, state, node in a graph, symbol in a string
State / Phase	A condition or mode a carrier or system can occupy; a way of being at a moment in time.	energy level, thermodynamic phase, ecological steady state, political stability state, cognitive state
Process / Event	A transformation or change over time; something that happens and alters states or carriers.	chemical reaction, mutation, erosion, migration, learning episode, market transaction, proof step
Structure / Configuration	A stable or semi-stable pattern of relationships among parts; the arrangement that gives form or constraint.	lattice, network, syntax tree, institutional hierarchy, anatomical structure, graph topology
System / Assembly	A multi-component entity with internal organization and interdependent parts.	solar system, cell, ecosystem, economy, polity, neural network, multi-agent model
Regime / Mode	A characteristic pattern of behavior or operation of a system under specific conditions.	laminar flow vs turbulence, firing modes, business cycles, political regimes, stable manifold vs chaotic regime
Role / Function / Position	A relational or functional slot that an entity occupies within a structure or system.	predator, prey, enzyme active site, consumer, producer, voter, bureaucrat, subject/object in grammar
Representation / Model	A formal or symbolic construction that encodes a system for prediction, computation, or reasoning.	equation, model, simulation, algorithm, grammar, proof system, differential equation

Descriptive Class Axes

How scientific entities occupy fundamental behavioral states

Axis B defines the binary regimes that every scientific entity must occupy when it appears in a model or explanation.
These regimes are not optional—they are the basic structural conditions that determine how a system behaves, how it evolves, and which mathematical tools apply to it.

Every descriptive class on this axis consists of two mutually exclusive states.
Each state represents a distinct mode of behavior:

• Micro vs Macro describes scale.
• Discrete vs Continuous describes the form of change.
• Equilibrium vs Non-equilibrium describes whether forces balance or drive evolution.
• Open vs Closed describes boundary interaction.
• Deterministic vs Stochastic describes predictability.
• Local vs Global describes interaction range.
• Linear vs Nonlinear describes response structure.
• Classical vs Quantum describes the underlying physical regime.

In scientific reasoning, every phenomenon must be placed on one side of each binary.
There is no “in between”: a process is either discrete or continuous in the model being used; a system is either open or closed as defined by its boundaries; behavior is either deterministic or stochastic in its governing equations.

The table below presents each descriptive class with its two labeled states and a clear, precise statement of what each state means.
This ensures no ambiguity when classifying entities and aligns all scientific domains under a common behavioral vocabulary.

SAT – Domain – Categories – Descriptive Class Axes

Descriptive Class	Core Meaning	Examples Across Sciences	State 1 (Label → Meaning)	State 2 (Label → Meaning)
Micro / Macro	Scale of organization; individual units vs collective behavior.	electrons vs galaxies; cells vs tissues; households vs economies	Micro → Behavior determined by individual units or fine-scale components.	Macro → Behavior determined by aggregates, collective patterns, or large-scale structure.
Discrete / Continuous	Whether the system changes in steps or smoothly.	digital signals; genetics vs fluid flow; PDEs	Discrete → Changes occur in steps, counts, or distinct units.	Continuous → Changes occur smoothly, with uninterrupted variation or fields.
Equilibrium / Non-equilibrium	Whether the system rests in balance or is driven by flux or gradients.	thermodynamic equilibrium vs turbulence; steady-state vs oscillatory systems	Equilibrium → Internal forces or flows balance; no net change in state.	Non-equilibrium → Driven by gradients or flux; system evolves or dissipates.
Open / Closed	Whether the system exchanges matter/energy/information with its environment.	open reactor vs sealed container; open vs autarkic economy	Open → Exchanges matter, energy, or information with the environment.	Closed → Isolated from exchange; boundary prevents transfer.
Deterministic / Stochastic	Whether outcomes follow exact laws or involve randomness.	Newtonian motion vs Brownian motion; deterministic vs Monte Carlo	Deterministic → Outcomes follow exact rules with no randomness.	Stochastic → Outcomes involve randomness, noise, or probabilistic branching.
Local / Global	Whether interactions are short-range or system-wide.	particle collisions vs gravitational fields; local markets vs global contagion	Local → Interactions confined to nearby or short-range relationships.	Global → Interactions propagate across the entire system or long-range structure.
Linear / Nonlinear	Whether responses scale proportionally or exhibit thresholds/chaos.	linear circuits vs turbulence; linear regression vs neural nets	Linear → Responses scale proportionally; superposition holds.	Nonlinear → Responses distort, amplify, saturate, or become chaotic.
Classical / Quantum	Whether behavior follows classical determinacy or quantum rules.	classical mechanics vs quantum computing; ray vs quantum optics	Classical → Behavior follows classical determinacy and continuous states.	Quantum → Behavior exhibits superposition, entanglement, or quantized states.

Unified Ontological Binary Matrix

The Unified Ontological Binary Matrix shows how every scientific entity can be characterized by combining its ontological type (what kind of thing it is) with its binary behavioral class (how it behaves). The result is a 64-slot grid in which each cell contains real scientific examples that represent the intersection of a fundamental type—Carrier, State, Process, Structure, System, Regime, Role, or Representation—with one of the eight binary descriptive contrasts that govern scientific behavior, such as Micro/Macro or Deterministic/Stochastic.

By placing concrete examples directly in the matrix, the framework demonstrates how phenomena from physics, biology, chemistry, economics, linguistics, and the social sciences naturally fall into the same underlying ontological structure. This shows that the sciences differ in subject matter, but share a common organizational logic. The matrix serves as an intuitive reference for recognizing how any concept fits into the broader unified system.

SAT – Domain – Categories – Unified Ontological Binary Matrix Examples

Ontological Type ↓ / Binary Class →	Micro / Macro	Discrete / Continuous	Equilibrium / Non-equilibrium	Open / Closed	Deterministic / Stochastic	Local / Global	Linear / Nonlinear	Classical / Quantum
Carrier / Substance	electron / planet	digital bit / fluid parcel	crystal lattice / heated gas	open chemical cell / sealed container	billiard ball motion / Brownian particle	defect site / magnetic field line	resistor / nonlinear diode	baseball / electron
State / Phase	single-cell state / ecological zone	quantized energy level / temperature field	vapor–liquid equilibrium / plasma sheath	nutrient-rich state / isolated mixture	stable fixed point / random drift state	local weather cell / global climate band	harmonic oscillation state / chaotic state	classical solid phase / Bose–Einstein condensate
Process / Event	protein folding / mountain uplift	reaction step / diffusion	reversible compression / turbulent cascade	nutrient uptake / sealed-cycle reaction	radioactive decay curve / genetic drift event	local collision / planetary migration	wave propagation / shock formation	classical collision / tunneling event
Structure / Configuration	microtubule / galaxy spiral arm	graph network / manifold	crystal symmetry / reaction–diffusion pattern	open neural network / closed lattice	syntax tree / stochastic social network	local cluster / world trade network	linear circuit / neural network	classical geometry / entanglement graph
System / Assembly	cell / ecosystem	agent-based model / fluid continuum	stable ecosystem / climate oscillation	open economy / autarkic economy	ideal ODE model / stochastic SDE model	local community / global supply chain	linear control system / climate system	steam engine / quantum computer
Regime / Mode	micro-eddies / jet stream	spike firing mode / shear-flow regime	laminar flow / turbulence	open convection / isothermal closed mode	periodic oscillator / stochastic drift	local weather regime / global monsoon system	linear wave regime / nonlinear shock regime	classical hydrodynamics / quantum Hall regime
Role / Function	enzyme active site / organ system role	discrete voter category / continuous ideology position	market-clearing role / crisis-trigger role	importer / closed-border actor	bureaucratic rule-follower / random influencer	neighborhood broker / global decision hub	linear-response role / nonlinear strategic role	classical observer / quantum measurement role
Representation / Model	micro-simulation / macro-model	difference equation / PDE	equilibrium solution / nonequilibrium solver	open-boundary simulation / closed-boundary simulation	deterministic algorithm / Monte Carlo model	local CFD mesh / global climate model	linear regression / nonlinear ODE solver	Newtonian model / QFT model

The binary-definition tables translate the abstract structure of the Unified Ontological Binary Matrix into clear conceptual meaning. Each binary axis—Micro/Macro, Discrete/Continuous, Equilibrium/Non-equilibrium, Open/Closed, Deterministic/Stochastic, Local/Global, Linear/Nonlinear, Classical/Quantum—describes a fundamental way that scientific phenomena can exist or behave.

But these contrasts only become analytically useful when they are applied to the eight ontological types (Carrier, State, Process, Structure, System, Regime, Role, Representation). A “Micro-Process” is not just “small” and a “Macro-Process” is not just “large”—they describe different kinds of causal organization. The same is true across every type: the meaning of “Local,” “Open,” “Nonlinear,” or “Quantum” changes depending on whether we are talking about a system, a structure, a role, or a representation.

The tables below provide the precise definitions for these combinations.
Each row takes one ontological type, and each column gives the two definitions that specify what that type is under a given binary contrast. This makes every cell of the matrix a clearly articulated conceptual category instead of a label.

With these definitions in place, the Unified Ontological Binary Matrix becomes a functional analytical tool:

• it tells you how a phenomenon should be understood,
• how it behaves,
• what governs it,
• and what scientific regime it belongs to.

The result is a complete, systematic vocabulary for describing scientific phenomena across all domains—natural, social, and formal—using a single, unified logical structure.

Explore the Unified Ontological Binary Matrix Here

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			Element
			Scope Category
			Sub-Item	Categories
Science Name Link	Branch Name Link	Field Name Link	Definition	The basic ontological types used to classify domain elements (substances, processes, relations, structures).
Natural Sciences	Physics	Classical Physics	Classical Mechanics	Systems are categorized as particles, rigid bodies, many-body systems, conservative vs non-conservative, constrained systems, and central-force systems.
Natural Sciences	Physics	Classical Physics	Classical Electromagnetism	Static vs time-varying fields; localized vs continuous sources; near-field vs far-field regions; conductors vs insulators vs dielectrics; free vs bound charge; wave vs quasistatic regimes.
Natural Sciences	Physics	Classical Physics	Classical Thermodynamics	Open, closed, and isolated systems; equilibrium vs non-equilibrium states; phases and phase boundaries; reversible vs irreversible processes; intensive vs extensive variables.
Natural Sciences	Physics	Classical Physics	Statistical Mechanics (Classical)	Microstates vs macrostates; ensembles (microcanonical, canonical, grand canonical); interacting vs non-interacting systems; ergodic vs non-ergodic behavior; equilibrium vs non-equilibrium systems.
Natural Sciences	Physics	Classical Physics	Optics (Classical Wave Theory)	Wave vs ray descriptions; coherent vs incoherent light; monochromatic vs broadband; birefringent vs isotropic media; linear vs nonlinear media; plane, spherical, and cylindrical waves; polarization categories (linear, circular, elliptical).
Natural Sciences	Physics	Classical Physics	Acoustics	Longitudinal vs transverse waves, plane waves vs spherical waves, propagating vs standing waves, continuous vs impulsive sources, fluid acoustics vs structural acoustics, and linear vs nonlinear regimes.
Natural Sciences	Physics	Classical Physics	Continuum Mechanics	Fluid vs solid materials, elastic vs plastic behavior, Newtonian vs non-Newtonian fluids, isotropic vs anisotropic materials, compressible vs incompressible continua, linear vs nonlinear systems.
Natural Sciences	Physics	Classical Physics	Classical Field Theory	Scalar vs vector vs tensor fields, static vs dynamic fields, conservative vs non-conservative fields, source-free vs source-driven fields, linear vs nonlinear fields, and local vs global field structures.
Natural Sciences	Physics	Classical Physics	Pre-Relativistic Frameworks	Particles vs rigid bodies, forces vs potentials, absolute space vs relative motion, wave phenomena vs particle motion, instantaneous action vs mediated interaction, inertial frames vs non-inertial frames defined by classical criteria.
Natural Sciences	Physics	Modern & Fundamental Physics	Quantum Mechanics	Pure vs mixed states, bound vs scattering states, fermions vs bosons, discrete vs continuous spectra, coherent vs decohered systems, isolated vs open quantum systems.
Natural Sciences	Physics	Modern & Fundamental Physics	Relativistic Quantum Mechanics	Particle vs antiparticle states, positive-energy vs negative-energy solutions, spinor vs scalar wave equations, free vs interacting relativistic particles, and relativistic bound vs scattering states.
Natural Sciences	Physics	Modern & Fundamental Physics	Special Relativity	Inertial vs non-inertial frames, timelike vs lightlike vs spacelike intervals, relativistic vs non-relativistic velocities, moving clocks vs stationary clocks, and length-contracted vs rest-length objects.
Natural Sciences	Physics	Modern & Fundamental Physics	General Relativity	Timelike, spacelike, and lightlike intervals; inertial vs non-inertial observers; vacuum vs matter-filled spacetimes; weak-field vs strong-field regimes; stationary vs dynamic spacetimes.
Natural Sciences	Physics	Modern & Fundamental Physics	Quantum Field Theory (QFT)	Fermion vs boson fields, scalar vs vector vs spinor fields, gauge vs matter fields, physical vs unphysical gauge degrees of freedom, renormalizable vs non-renormalizable interactions, perturbative vs non-perturbative regimes.
Natural Sciences	Physics	Modern & Fundamental Physics	Particle Physics (High-Energy Physics)	Fermions vs bosons, quarks vs leptons, stable vs unstable particles, charged vs neutral particles, Standard Model particles vs beyond-Standard-Model candidates, and strong vs weak vs electromagnetic interaction channels.
Natural Sciences	Physics	Modern & Fundamental Physics	Nuclear Physics	Stable vs unstable nuclei, isotopes vs isotones vs isobars, alpha/beta/gamma decay types, fission vs fusion processes, collective nuclear modes vs single-particle excitations, and neutron-rich vs proton-rich systems.
Natural Sciences	Physics	Modern & Fundamental Physics	Quantum Statistical Physics	Bosonic vs fermionic systems, normal vs condensed phases, superfluid vs normal fluid, degenerate gases vs thermal gases, weakly interacting vs strongly interacting systems, and ordered vs disordered quantum phases.
Natural Sciences	Physics	Modern & Fundamental Physics	Quantum Optics	Coherent vs incoherent states, classical vs nonclassical light, single-photon vs multi-photon regimes, free-space vs cavity modes, continuous-variable vs discrete-variable systems, and weak vs strong coupling regimes.
Natural Sciences	Physics	Modern & Fundamental Physics	Quantum Information Science	Physical qubit types (superconducting, trapped ion, photonic, spin-based), quantum protocols (computation, communication, sensing), error types (bit-flip, phase-flip), and system classifications such as NISQ devices vs fault-tolerant architectures.
Natural Sciences	Physics	Theoretical & Mathematical Physics	Symmetry & Group Theory	Continuous vs discrete groups, internal vs spacetime symmetries, Abelian vs non-Abelian groups, global vs local symmetries, finite vs infinite groups, and irreducible vs reducible representations.
Natural Sciences	Physics	Theoretical & Mathematical Physics	Gauge Theory	Fields, interaction processes, relations including symmetry transformations and covariant derivatives, and structures such as groups and bundles.
Natural Sciences	Physics	Theoretical & Mathematical Physics	String Theory	Extended objects, processes involving splitting and joining of strings, relations defined by dualities, and geometric structures such as compact spaces and higher-dimensional manifolds.
Natural Sciences	Physics	Theoretical & Mathematical Physics	Differential Geometry in Physics	Geometric objects, processes such as parallel transport, relations such as metric relations and connection laws, and structural elements such as bundles and coordinate charts.
Natural Sciences	Physics	Theoretical & Mathematical Physics	Statistical Field Theory	Continuous fields, stochastic processes, interaction terms, symmetry classes, renormalization structures, and universality classes describing behavior independent of microscopic detail.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Mathematical Foundations of Quantum Mechanics	States, observables, transformations, measurement outcomes, operator classes, and structural relations such as commutation and algebraic rules.
Natural Sciences	Physics	Condensed Matter & Materials Physics	General Mathematical Physics	Categories include mathematical objects, equations, transformations, symmetry groups, geometric structures, topological classes, and algebraic frameworks used to describe systems.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Solid-State Physics	Substances such as crystals and amorphous solids, processes such as transport and scattering, relations such as band-structure interactions, and structural elements such as lattices, defects, and symmetry groups.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Semiconductor Physics	Materials, carriers, junctions, optical transitions, scattering processes, band structures, and device-relevant structures such as depletion regions and potential barriers.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Magnetism & Spin Physics	Materials, spin interactions, magnetic phases, excitations, domain structures, and processes such as spin transport and relaxation.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Superconductivity	Phases, excitations, condensates, vortices, symmetry states, order parameters, and collective modes associated with superconducting behavior.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Soft Matter Physics	Soft materials, phases, microstructures, interactions, deformation processes, self-assembly pathways, and emergent collective behaviors.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Nanomaterials & Nanostructures	Nanostructures, surfaces, interfaces, confinement regimes, collective modes, and nanoscale processes such as diffusion, adsorption, and charge transfer.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Strongly Correlated Electron Systems	Phases, excitations, order parameters, lattice electron couplings, collective behaviors, and emergent structures such as magnetic order, charge order, or topological states.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Topological Matter	Topological phases, bulk properties, boundary states, protected modes, nodal features, and response signatures such as quantized conductance.
Natural Sciences	Physics	Condensed Matter & Materials Physics	Materials Science (Physical Perspective)	Materials classes, phases, microstructures, processes such as deformation or diffusion, relations linking structure and properties, and structural features such as defects or interfaces.
Natural Sciences	Physics	Astrophysics & Cosmology	Stellar Astrophysics	Stellar types, evolutionary phases, internal processes, observable features, energy transport mechanisms, nuclear reaction chains, and remnant classes.
Natural Sciences	Physics	Astrophysics & Cosmology	Galactic Astrophysics	Galactic components, stellar populations, gas phases, structural features, dynamical processes, and interactions such as inflows, outflows, and internal feedback.
Natural Sciences	Physics	Astrophysics & Cosmology	Extragalactic Astrophysics	Galaxy types, cluster types, large scale structures, intergalactic medium phases, dynamical processes, and interaction or merger classes.
Natural Sciences	Physics	Astrophysics & Cosmology	Cosmology	Cosmic components, epochs, large scale structures, physical processes, symmetry regimes, and matter energy partitions.
Natural Sciences	Physics	Astrophysics & Cosmology	High-Energy Astrophysics	High energy sources, transient events, steady emitters, radiation processes, particle acceleration mechanisms, and compact object environments.
Natural Sciences	Physics	Astrophysics & Cosmology	Gravitational Astrophysics	Planet types, atmospheric regimes, surface processes, orbital types, evolutionary pathways, and internal structural layers.
Natural Sciences	Physics	Astrophysics & Cosmology	Planetary Science & Exoplanets	Planet types, atmospheric regimes, surface processes, orbital architectures, formation pathways, and structural layers such as crust, mantle, and core.
Natural Sciences	Physics	Astrophysics & Cosmology	Astrochemistry & Interstellar Medium Physics	ISM phases, chemical networks, reaction types, molecular families, dust populations, heating and cooling processes, and physical structures such as clouds, filaments, and shells.
Natural Sciences	Physics	Astrophysics & Cosmology	Astrobiology	Life detection targets, biosignatures, abiotic mimics, habitability factors, planetary environments, chemical networks, and biological or prebiotic processes.
Natural Sciences	Physics	Plasma & Fluid Physics	Fluid Dynamics	Fluid types, flow regimes, boundary conditions, transport processes, structural flow features, and dynamic behaviors such as turbulence, laminar flow, or shocks.
Natural Sciences	Physics	Plasma & Fluid Physics	Hydrodynamics (Ideal Fluids)	Conducting fluid states, MHD wave modes, magnetic topologies, plasma regimes, instabilities, and reconnection geometries.
Natural Sciences	Physics	Plasma & Fluid Physics	Magnetohydrodynamics (MHD)	Conducting fluid states, wave modes, turbulence regimes, reconnection regimes, magnetic topologies, and plasma features such as filaments or sheets.
Natural Sciences	Physics	Plasma & Fluid Physics	Plasma Physics (General)	Plasma regimes, wave modes, instability types, transport processes, magnetization regimes, collisional vs collisionless plasmas, and geometric structures such as filaments and sheets.
Natural Sciences	Physics	Plasma & Fluid Physics	Space & Astrophysical Plasmas	Plasma regimes, wave modes, instability types, magnetic structures, shock types, reconnection environments, and astrophysical system classes such as winds, disks, jets, and coronae.
Natural Sciences	Physics	Plasma & Fluid Physics	Fusion Plasma Physics	Confinement regimes, heating methods, plasma regions, turbulence modes, instability classes, reaction channels, and plasma-material interaction processes.
Natural Sciences	Physics	Plasma & Fluid Physics	Computational Fluid & Plasma Physics	Fluid models, kinetic models, hybrid models, grid types, solver classes, turbulence closures, boundary conditions, physical modules, and numerical schemes.
Natural Sciences	Physics	Plasma & Fluid Physics	Non-Newtonian & Complex Fluids	Fluid classes (viscoelastic, shear-thinning, shear-thickening, thixotropic, yield-stress, granular), microstructural mechanisms, flow regimes, constitutive behaviors, and deformation histories.
Natural Sciences	Physics	Plasma & Fluid Physics	High-Energy-Density Physics (HEDP)	States of matter (solid, liquid, warm dense matter, plasma), shock types, compression regimes, radiation hydrodynamics regimes, instability classes, and material response categories under extreme load.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Biophysics	Structural biology elements, dynamic biochemical processes, transport and signaling processes, mechanical systems, electrophysiological systems, and emergent collective behaviors.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Medical Physics	Imaging modalities, radiation types, detection methods, dose delivery mechanisms, calibration standards, tissue response models, and safety classifications.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Geophysics	Material layers, wave types, tectonic regimes, stress regimes, deformation modes, geomagnetic domains, hydrologic reservoirs, and geodynamic processes.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Optics & Photonics	Wave types, optical components, propagation regimes, coherence classes, nonlinear processes, quantum states, photonic materials, and imaging modalities.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Computational Physics	Numerical methods, discretization schemes, solver classes, boundary conditions, model types, physical regimes, and simulation architectures.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Engineering Physics	System types, material categories, device classes, mechanical regimes, electromagnetic regimes, thermal regimes, quantum vs classical behavior ranges, and linear vs nonlinear system classes.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Chemical Physics	Molecular species, reaction pathways, interaction types, energy states, electronic configurations, vibrational modes, statistical ensembles, and condensed-phase structures.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Environmental & Climate Physics	Climate subsystems, atmospheric layers, ocean layers, radiation types, hydrologic cycle components, circulation regimes, forcing types, feedback classes, and variability modes.
Natural Sciences	Physics	Interdisciplinary & Applied Physics	Applied Materials Physics	Material classes (metals, ceramics, polymers, semiconductors, composites), microstructural categories (grains, phases, inclusions), functional categories (optical, magnetic, electronic, structural), and physical process categories (diffusion, deformation, phase transformation).
Natural Sciences	Chemistry	Physical Chemistry	Quantum Chemistry	Atoms, ions, molecules, electronic states, eigenstates, excited states, basis functions, PES regions.
Natural Sciences	Chemistry	Physical Chemistry	Statistical Mechanics	Ensembles (microcanonical, canonical, grand canonical), states, phases, degrees of freedom, equilibrium vs nonequilibrium regimes.
Natural Sciences	Chemistry	Physical Chemistry	Thermodynamics	Systems (open, closed, isolated), processes (reversible, irreversible), phases, equilibria, constraints.
Natural Sciences	Chemistry	Physical Chemistry	Kinetics & Reaction Dynamics	Elementary vs. complex reactions, unimolecular/bimolecular steps, chain processes, catalytic cycles, energy-transfer events.
Natural Sciences	Chemistry	Physical Chemistry	Spectroscopy	Absorption, emission, scattering, fluorescence, phosphorescence, Raman, IR, NMR, UV-Vis, X-ray, microwave, ultrafast and nonlinear processes.
Natural Sciences	Chemistry	Physical Chemistry	Electrochemistry	Redox reactions, galvanic and electrolytic cells, electrode processes, surface reactions, mass transport regimes (diffusion, migration, convection).
Natural Sciences	Chemistry	Physical Chemistry	Surface & Interface Science	Surfaces, interfaces, adsorbate–surface complexes, defects, grain boundaries, thin films, heterogeneous catalytic sites, liquid–solid and gas–solid interfaces.
Natural Sciences	Chemistry	Physical Chemistry	Colloid & Solution Chemistry	Solutions, colloids, suspensions, emulsions, gels, micellar systems, polyelectrolytes, electrolytes, surfactant assemblies.
Natural Sciences	Chemistry	Physical Chemistry	Chemical Physics	Bound vs unbound states, electronic/vibrational/rotational levels, scattering events, coherent vs incoherent processes, adiabatic vs nonadiabatic regimes.
Natural Sciences	Chemistry	Organic Chemistry	Structural & Mechanistic Organic Chemistry	Functional groups, reaction types (substitution, addition, elimination, rearrangements), reactive intermediates, mechanistic steps, stereoelectronic effects.
Natural Sciences	Chemistry	Organic Chemistry	Stereochemistry & Conformational Analysis	Stereoisomers, conformational isomers, enantiomers, diastereomers, conformers, atropisomers, anomers, cyclic conformations (chair, boat, twist-boat), symmetry classes.
Natural Sciences	Chemistry	Organic Chemistry	Synthetic Organic Chemistry	Reaction classes (addition, substitution, elimination, rearrangement, oxidation/reduction), synthetic strategies, protecting-group chemistries, catalytic cycles, cascade processes.
Natural Sciences	Chemistry	Organic Chemistry	Physical Organic Chemistry	Reaction families (SN1/SN2, E1/E2, addition, rearrangement), substituent effects, kinetic regimes, thermodynamic profiles, reactive intermediate classes.
Natural Sciences	Chemistry	Organic Chemistry	Organometallic Organic Chemistry	Catalytic cycles, ligand classes (σ-donors, π-acceptors), organometallic reaction types (oxidative addition, reductive elimination, insertion, β-hydride elimination), coordination geometries.
Natural Sciences	Chemistry	Organic Chemistry	Polymer Chemistry (Carbon-based)	Polymer classes (addition, condensation, radical, ionic), microstructures (isotactic, syndiotactic, atactic), architectures (linear, branched, crosslinked, block, graft), chain-growth vs step-growth.
Natural Sciences	Chemistry	Organic Chemistry	Bioorganic Chemistry	Biomolecular families (peptides, carbohydrates, nucleic acids, lipids), enzyme reaction types, cofactors, metabolic intermediates, bioorthogonal reactions, biomimetic catalysts.
Natural Sciences	Chemistry	Organic Chemistry	Natural Products Chemistry	Terpenoids, polyketides, alkaloids, phenylpropanoids, nonribosomal peptides, ribosomal peptides, carbohydrates, lipids, shikimate-pathway products, mixed biosynthetic hybrids.
Natural Sciences	Chemistry	Organic Chemistry	Medicinal Chemistry	Drug classes, target families (GPCRs, kinases, ion channels), pharmacophores, bioisosteric groups, ADMET categories, structural alerts, prodrug types, reactive metabolite classes.
Natural Sciences	Chemistry	Inorganic Chemistry	Main-Group Chemistry	Alkali metals, alkaline earths, p-block families (boron chemistry, carbon/silicon chemistry, pnictogens, chalcogens, halogens, noble gases), clusters, hypervalent compounds, Z-intl phases.
Natural Sciences	Chemistry	Inorganic Chemistry	Transition-Metal Chemistry	Coordination complexes, catalytic species, high-spin/low-spin systems, octahedral/tetrahedral/square-planar geometries, inner-/outer-sphere species, metal–metal bonded clusters.
Natural Sciences	Chemistry	Inorganic Chemistry	f-Block Chemistry	Lanthanide chemistry, actinide chemistry, coordination complexes, organof-element chemistry, high-oxidation-state actinides, mixed-valent clusters, 4f vs 5f bonding regimes.
Natural Sciences	Chemistry	Inorganic Chemistry	Coordination Chemistry	Monodentate/polydentate ligands, chelates, macrocycles, Werner-type complexes, high-spin/low-spin systems, inner-/outer-sphere species, supramolecular coordination assemblies.
Natural Sciences	Chemistry	Inorganic Chemistry	Solid-State Chemistry	Crystalline solids, amorphous solids, metals, semiconductors, insulators, ionic solids, molecular solids, covalent networks, layered materials, porous solids (MOFs/zeolites).
Natural Sciences	Chemistry	Analytical Chemistry	Qualitative Analysis	Functional-group tests, inorganic ion identification, organic structure determination, spectroscopic identification (MS/NMR/IR/UV–Vis), classical wet-chemistry tests, confirmatory analyses.
Natural Sciences	Chemistry	Analytical Chemistry	Quantitative Analysis	Calibration methods (external, internal, standard addition), titrimetric methods, gravimetry, volumetry, instrumental quantitative techniques (MS, NMR, IR, UV–Vis, electrochemical).
Natural Sciences	Chemistry	Analytical Chemistry	Separation Science	Chromatography (GC, LC, IC), electrophoresis, extraction (liquid–liquid, solid–liquid), distillation, filtration, dialysis, precipitation, membrane separations, sorption-based methods.
Natural Sciences	Chemistry	Analytical Chemistry	Instrumental Analysis	Spectroscopic (IR, UV–Vis, fluorescence), mass spectrometric, chromatographic, electroanalytical, thermal analytical, atomic spectrometric, hyphenated techniques (GC–MS, LC–MS).
Natural Sciences	Chemistry	Biochemistry	Structural Biochemistry	Structural motifs (α-helices, β-sheets, turns), domains, folds, nucleic-acid structural forms (A/B/Z-DNA, RNA motifs), macromolecular assemblies, intrinsically disordered regions, symmetry classes.
Natural Sciences	Chemistry	Biochemistry	Enzymology	Enzyme classes (oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases), regulatory enzymes, multi-enzyme complexes, catalytic mechanisms (acid–base, covalent, metal-ion catalysis, etc.).
Natural Sciences	Chemistry	Biochemistry	Metabolism & Bioenergetics	Catabolic vs anabolic pathways, central carbon metabolism, electron-transport processes, substrate-level phosphorylation, oxidative phosphorylation, fermentation pathways, metabolic cycles, transport mechanisms.
Natural Sciences	Chemistry	Biochemistry	Molecular Biology & Gene Expression	Genetic elements (genes, operons, enhancers, insulators), RNA types (mRNA, tRNA, rRNA, ncRNA, miRNA, lncRNA), regulatory systems (activators, repressors), chromatin states, transcriptional/epigenetic mechanisms.
Natural Sciences	Chemistry	Biochemistry	Cellular Biochemistry	Organelles (mitochondria, ER, Golgi, lysosomes), cytoskeletal systems, trafficking pathways, metabolic modules, signaling modules, degradation systems (proteasome/autophagy), membrane-transport categories.
Natural Sciences	Chemistry	Biochemistry	Membrane Biochemistry	Membrane types (plasma membrane, ER, Golgi, mitochondrial inner membrane, lysosomal), lipid classes, membrane-protein classes (integral, peripheral, GPI-anchored), transport mechanisms (channels, carriers, pumps).
Natural Sciences	Chemistry	Biochemistry	Protein Chemistry	Structural classes (fibrous, globular, membrane proteins), functional classes (enzymes, receptors, transporters), PTM categories (phosphorylation, glycosylation, ubiquitination), peptide classes, folding types, oligomerization states.
Natural Sciences	Chemistry	Biochemistry	Biochemical Genetics	Mutation types (missense, nonsense, frameshift), inheritance types (dominant, recessive, X-linked, mitochondrial), metabolic disorders, enzyme-deficiency classes, pathway modules, regulatory mutations, modifier genes.
Natural Sciences	Earth & Space Sciences	Geology	Mineralogy & Crystallography	Mineral groups (silicates, carbonates, oxides, sulfides, etc.), crystal systems (cubic, tetragonal, hexagonal), symmetry classes, polymorph families, solid-solution series, defect types (vacancies, substitutions).
Natural Sciences	Earth & Space Sciences	Geology	Petrology	Igneous rocks (intrusive/extrusive), metamorphic rocks (foliated/non-foliated), sedimentary rocks (clastic/chemical/biogenic), metamorphic facies, magma types, protolith categories, reaction types, melting/solidification regimes.
Natural Sciences	Earth & Space Sciences	Geology	Structural Geology & Tectonics	Fault types (normal, reverse, thrust, strike-slip), fold types (anticline, syncline, monocline), deformation regimes (brittle/ductile), plate boundaries (divergent, convergent, transform), structural fabrics, tectonic settings.
Natural Sciences	Earth & Space Sciences	Geology	Sedimentology & Stratigraphy	Sediment types (clastic, chemical, biogenic), depositional environments (fluvial, deltaic, marine, aeolian, glacial), sedimentary structures (ripples, dunes, cross-bedding, graded bedding), stratigraphic units (formations, members), sequence types (transgressive, regressive).
Natural Sciences	Earth & Space Sciences	Geology	Geomorphology	Landform types (fluvial, coastal, aeolian, glacial, periglacial, karst, hillslope), process domains (erosional, depositional, transport-limited, supply-limited), climate regimes, relief classes, tectonic settings, drainage patterns.
Natural Sciences	Earth & Space Sciences	Geology	Geophysics	Geophysical domains (seismology, gravity, magnetics, electromagnetics, heat flow, geodesy, geodynamics); subsurface structures (crust, mantle, core); material types (elastic, viscoelastic, viscous, conductive); wave types (P, S, surface waves).
Natural Sciences	Earth & Space Sciences	Geology	Geochemistry	Geochemical reservoirs (crust, mantle, hydrosphere, atmosphere, biosphere), geochemical processes (weathering, precipitation, adsorption, oxidation, reduction), isotope systems (radiogenic/stable), mineral groups, fluid types, chemical facies.
Natural Sciences	Earth & Space Sciences	Geology	Paleontology	Fossil types (body, trace, chemical), taxonomic groups, taphonomic pathways, depositional environments, biostratigraphic zones, evolutionary clades, functional groups, preservational modes (permineralization, mold/cast, carbonization).
Natural Sciences	Earth & Space Sciences	Geology	Hydrogeology	Aquifer types (confined, unconfined, perched), porosity types (primary/secondary), flow regimes (laminar/turbulent), rock types (karst, fractured, porous media), hydrostratigraphic units, contamination types (DNAPLs, LNAPLs, dissolved plumes).
Natural Sciences	Earth & Space Sciences	Geology	Economic & Applied Geology	Ore-deposit types (porphyry, VMS, SEDEX, epithermal, skarn, orogenic gold, IOCG), petroleum system elements (source, reservoir, seal, trap), mineral resources (metallic, non-metallic, energy), exploration methods, mining/engineering settings.
Natural Sciences	Earth & Space Sciences	Meteorology	Dynamic Meteorology	Atmosphere as a rotating stratified fluid; motion described through forces, flows, waves, instabilities, and balanced dynamical regimes (geostrophic, hydrostatic, gradient-wind, etc.).
Natural Sciences	Earth & Space Sciences	Meteorology	Thermodynamic Meteorology	Thermodynamic states (stable, neutral, unstable), phase-change processes, energy budgets, atmospheric layers (boundary layer, free troposphere), and cloud microphysical regimes.
Natural Sciences	Earth & Space Sciences	Meteorology	Cloud Physics & Microphysics	Particle types (droplets, crystals, graupel), phase categories (liquid, ice, mixed-phase), microphysical processes (condensation, deposition, freezing, aggregation), and cloud regimes (warm, cold, mixed-phase).
Natural Sciences	Earth & Space Sciences	Meteorology	Synoptic & Mesoscale Meteorology	Synoptic systems (cyclones, anticyclones, fronts), mesoscale systems (MCSs, supercells, sea breezes, mountain waves), dynamical regimes (baroclinic, barotropic, forced ascent, convectively driven), and boundary-layer structures.
Natural Sciences	Earth & Space Sciences	Meteorology	Atmospheric Physics & Chemistry	Gas-phase species, aerosol species, short-lived radicals, long-lived greenhouse gases, radiative processes (absorption, scattering, emission), chemical families (NOx, VOCs, halogens), and dynamical–radiative regimes.
Natural Sciences	Earth & Space Sciences	Meteorology	Climatology & Climate Dynamics	Climate regimes (tropical, extratropical, polar), internal variability modes (ENSO, MJO, NAO), forcing types (natural vs anthropogenic), feedback categories (albedo, water vapor, lapse rate, cloud), and slow vs fast climate responses.
Natural Sciences	Earth & Space Sciences	Oceanography	Physical Oceanography	Water masses, circulation regimes (wind-driven, thermohaline), wave types (surface gravity waves, internal waves, tsunamis), boundary layers (Ekman, benthic), stratification types (stable/unstable), mixing regimes, climate modes (ENSO, NAO).
Natural Sciences	Earth & Space Sciences	Oceanography	Chemical Oceanography	Nutrient systems (N, P, Si), carbon system species, redox systems (O₂, NO₃⁻/NO₂⁻, Mn/Fe cycles), trace metals, major ions, particulate/dissolved pools, organic vs inorganic fractions, conservative vs non-conservative elements.
Natural Sciences	Earth & Space Sciences	Oceanography	Biological Oceanography	Phytoplankton groups (diatoms, dinoflagellates, cyanobacteria), zooplankton groups (copepods, krill), microbial types, trophic levels, functional groups, bloom types, ecosystem types (pelagic, benthic), size classes (pico–macro).
Natural Sciences	Earth & Space Sciences	Oceanography	Geological Oceanography	Sediment types (terrigenous, biogenic, hydrogenous, authigenic, volcanogenic), depositional environments (shelf, slope, abyssal plain), tectonic settings (MORs, trenches, hotspots), sedimentary structures, stratigraphic units, seafloor morphologies.
Natural Sciences	Biology	Molecular Biology	Nucleic Acid Biology	DNA vs RNA, coding vs noncoding sequences, primary/secondary/tertiary structures, replication vs transcription pathways, modification types, damage categories, and enzyme–nucleic acid interaction classes.
Natural Sciences	Biology	Molecular Biology	Gene Regulation & Epigenetics	Cis-regulatory elements, trans-acting factors, activating vs repressing histone marks, open vs closed chromatin, short-term vs long-term regulation, locus-specific vs genome-wide epigenetic states, and heritable vs reversible regulatory mechanisms.
Natural Sciences	Biology	Molecular Biology	Protein Biology	Structural classes (α, β, mixed), functional classes (enzymes, receptors, transporters, scaffolds), folding states (native, misfolded, aggregated), interaction types (protein–protein, protein–ligand), and PTM categories (phosphorylation, acetylation, ubiquitination).
Natural Sciences	Biology	Molecular Biology	Molecular Complexes & Information Flow	Catalytic complexes, structural scaffolds, information-processing hubs, regulatory condensates, membrane-associated complexes, genome-maintenance machines, and dynamic signaling assemblies.
Natural Sciences	Biology	Molecular Biology	Molecular Methods & Technologies	Analytical methods, sequencing technologies, imaging modalities, amplification systems, gene-editing tools, purification platforms, single-molecule systems, microfluidics, biosensors, and synthetic-biology toolkits.
Natural Sciences	Biology	Cell Biology	Cell Structure & Organelles	Membrane-bound vs non-membrane-bound organelles; biosynthetic vs degradative compartments; cytoskeletal systems (actin, microtubules, intermediate filaments); trafficking structures (vesicles, coats, motors).
Natural Sciences	Biology	Cell Biology	Cellular Dynamics & Trafficking	Transport modes (motor-based, diffusive, flow-based), trafficking pathways (secretory, endocytic, recycling, degradative), vesicle types (clathrin, COPI, COPII), transport geometries (long-range vs. local), and membrane transition states (budding, docking, fusion).
Natural Sciences	Biology	Cell Biology	Cell Signaling & Communication	Signaling types (autocrine, paracrine, juxtacrine, endocrine), pathway families (GPCR, RTK, Wnt, Notch, TGF-β, NF-κB), messenger classes (ions, nucleotides, lipids), and regulatory modes (feedback, feedforward, cross-talk).
Natural Sciences	Biology	Cell Biology	Cell Cycle, Fate & Death	Cell-cycle phases (G1, S, G2, M), fate states (stem, progenitor, differentiated), death modalities (apoptosis, necroptosis, autophagy-associated death), checkpoint types (G1/S, G2/M, spindle assembly), lineage-commitment modes (binary, graded, stochastic).
Natural Sciences	Biology	Cell Biology	Cell Interactions & Microenvironment	Interaction types (adhesive, mechanical, chemical), junction classes (tight, adherens, gap), ECM categories (basement membrane, interstitial matrix), microenvironment types (niche, inflammatory, fibrotic, tumor), force modes (tension, shear, compression).
Natural Sciences	Biology	Cell Biology	Cell Morphology & Motility	Motility modes (mesenchymal, amoeboid, collective, swimming), protrusion types (lamellipodia, filopodia, blebs), cytoskeletal systems (actin, microtubules, intermediate filaments), adhesion classes (focal adhesions, nascent adhesions), polarity regimes (front–rear, rotational, multi-axial).
Natural Sciences	Biology	Genetics & Evolution	Classical & Transmission Genetics	Trait types (monogenic, polygenic), allele interactions (dominant, recessive, codominant), inheritance modes (autosomal, sex-linked), linkage categories (linked, unlinked).
Natural Sciences	Biology	Genetics & Evolution	Population Genetics	Population types (panmictic, structured, subdivided), evolutionary forces (mutation, migration, drift, selection, nonrandom mating), selection modes (directional, stabilizing, balancing), mating systems (random, assortative, disassortative, inbreeding).
Natural Sciences	Biology	Genetics & Evolution	Quantitative Genetics	Trait types (continuous, threshold), variance components (additive, dominance, epistatic, environmental), selection regimes (directional, stabilizing, disruptive), genetic architectures (polygenic, oligogenic), covariance structures (phenotypic, genetic).
Natural Sciences	Biology	Genetics & Evolution	Genomic Evolution & Comparative Genomics	Mutation classes (point, indel, structural), homology types (orthology, paralogy, xenology), genomic features (coding, noncoding, regulatory, repetitive), rearrangement types (inversions, translocations, fusions), evolutionary models (neutral, nearly neutral, adaptive).
Natural Sciences	Biology	Genetics & Evolution	Phylogenetics & Systematics	Tree types (gene trees, species trees), group types (monophyletic, paraphyletic, polyphyletic), character types (molecular, morphological, behavioral), classification ranks (species → domain), evolutionary model classes (parsimony, likelihood, Bayesian).
Natural Sciences	Biology	Genetics & Evolution	Macroevolution & Speciation Theory	Speciation types (allopatric, sympatric, parapatric, peripatric), isolation types (prezygotic, postzygotic), macroevolutionary models (adaptive radiation, stasis, gradualism, punctuated equilibrium), lineage categories (sister clades, stem vs crown groups).
Natural Sciences	Biology	Physiology	Cellular & Tissue Physiology	Cell types, tissue types (epithelial, connective, muscle, nervous), transport processes, mechanical behaviors, signaling modes, junction types, and extracellular structures.
Natural Sciences	Biology	Physiology	Neurophysiology	Excitatory vs inhibitory neurons, chemical vs electrical synapses, ion-channel classes, neurotransmitter systems, network motifs, firing types, and sensory–motor pathways.
Natural Sciences	Biology	Physiology	Endocrine & Regulatory Physiology	Hormone types (peptide, steroid, amine), secretion modes (endocrine, paracrine, autocrine), regulatory axes, receptor classes, feedback types (positive/negative), and rhythmic regulation (ultradian, circadian).
Natural Sciences	Biology	Physiology	Cardiovascular & Respiratory Physiology	Pressure-driven vs diffusion-driven transport, systemic vs pulmonary circuits, elastic vs muscular arteries, ventilation modes, control systems (neural, endocrine), flow regimes (laminar vs turbulent), and gas-transport categories.
Natural Sciences	Biology	Physiology	Metabolic & Energetic Physiology	Catabolic vs anabolic pathways, aerobic vs anaerobic metabolism, substrate classes, thermogenic mechanisms, storage forms, regulatory hormones, and metabolic states (fed/fasted, rest/exercise).
Natural Sciences	Biology	Physiology	Renal, Fluid & Homeostatic Physiology	Filtration vs reabsorption vs secretion, cortical vs juxtamedullary nephrons, intracellular vs extracellular fluid compartments, electrolyte classes, acid–base disturbances, and regulatory hormone classes.
Natural Sciences	Biology	Developmental Biology	Cell Fate & Lineage Specification	Fate states (pluripotent, multipotent, progenitor, terminal), signaling modes (autocrine, paracrine, juxtacrine), lineage-branching patterns, regulatory categories (master regulators, modulators), division types (symmetric vs asymmetric), specification strategies (deterministic vs stochastic).
Natural Sciences	Biology	Developmental Biology	Pattern Formation & Embryonic Axes	Gradient types (long-range, short-range, opposing), axis types (AP, DV, LR), patterning mechanisms (reaction–diffusion, French flag, relay signaling), segmentation systems (clock-and-wavefront), organizer types (Spemann organizer, node), polarity-establishment modes.
Natural Sciences	Biology	Developmental Biology	Morphogenesis & Tissue-Level Mechanics	Tissue types (epithelial, mesenchymal), deformation modes (folding, bending, convergent extension, spreading), force-generation mechanisms (actomyosin contraction, crawling, pushing), mechanical regimes (elastic, viscoelastic, fluid-like), morphogenetic modules (intercalation, constriction, migration).
Natural Sciences	Biology	Developmental Biology	Organogenesis & Multi-Tissue Assembly	Organ types (tubular, branched, layered, cavity-forming), assembly modules (epithelial–mesenchymal interactions, branching units, lumenogenesis strategies), tissue roles (inductive, supportive, boundary-forming), communication types (paracrine, juxtacrine, mechanical).
Natural Sciences	Biology	Developmental Biology	Growth, Timing, Regeneration & Life-Cycle Transitions	Growth modes (isometric, allometric), timing systems (circadian, developmental, hormonal), regeneration types (epimorphic, compensatory, morphallactic), life-cycle stages (embryonic, larval, metamorphic, adult, senescent), checkpoint types (size, nutritional, developmental).
Natural Sciences	Biology	Developmental Biology	Evolutionary Development (Evo–Devo)	Types of developmental change (heterochrony, heterotopy, heterometry, heterotypy), homology categories (serial, deep, molecular), modular units (segments, appendage modules), evolutionary trajectories (co-option, innovation, loss), patterning mechanisms (axis, segmentation, organ-specific GRNs).
Natural Sciences	Biology	Ecology	Organismal Ecology	Behavioral strategies, physiological traits, morphological adaptations, habitat types, niche dimensions, resource types, stressors (thermal, hydric, predation), and environmental gradients.
Natural Sciences	Biology	Ecology	Population Ecology	Population types (closed/open, stable/unstable), life-history strategies, density-dependent vs independent processes, demographic stages, reproductive strategies, and spatial population structures (patches, metapopulations).
Natural Sciences	Biology	Ecology	Community Ecology	Interaction types (competition, predation, mutualism), community types (trophic, functional, phylogenetic), diversity categories (alpha, beta, gamma), successional stages, and network structures (modular, nested).
Natural Sciences	Biology	Ecology	Ecosystem Ecology	Trophic levels, biogeochemical cycles, ecosystem types, energy pathways, nutrient pools (organic/inorganic), flux types (input/output/internal), and physical compartments (soil, water, atmosphere).
Natural Sciences	Biology	Ecology	Landscape & Spatial Ecology	Patch types, land-cover classes, connectivity types, spatial configurations (fragmented, aggregated, linear), dispersal modes, landscape gradients, and network structures (graph nodes/edges).
Natural Sciences	Biology	Ecology	Global Ecology & Earth-System Interactions	Biomes, biogeochemical cycles (carbon, nitrogen, phosphorus, water), climate zones, global flux pathways, feedback types (positive/negative), large-scale drivers (ENSO, monsoons), and Earth-system subsystems.
Formal Sciences	Logic	Proof Theory	Proof Calculi	Logical rules, structural rules, axioms, derivations, Hilbert systems, sequent systems, natural deduction rules, analytic tableaux expansions.
Formal Sciences	Logic	Proof Theory	Structural Proof Theory	Sequent structures, structural-rule families, proof transformations, analytic vs. non-analytic steps, cut vs. cut-free derivations, normal vs. non-normal forms.
Formal Sciences	Logic	Proof Theory	Proof Theory of Non-Classical Logics	Modal, intuitionistic, linear, affine, relevant, paraconsistent, paracomplete, many-valued calculi; labeled vs. unlabeled systems; deep vs. shallow inference; analytic vs. non-analytic rules.
Formal Sciences	Logic	Proof Theory	Ordinal & Strength Analysis	Ordinal notation systems, proof-theoretic ordinals, classification of theories by strength, reflection principles, induction schemas, recursion hierarchies (fast-growing, slow-growing), collapsing functions.
Formal Sciences	Logic	Proof Theory	Proof Complexity	Propositional proof systems, algebraic proof systems, geometric proof systems, semi-algebraic systems, bounded-depth Frege variants, Resolution variants (tree-like, regular), proof-system hierarchies, complexity-class correspondences.
Formal Sciences	Logic	Proof Theory	Automated & Interactive Reasoning	Automated theorem provers, SMT solvers, SAT solvers, interactive proof assistants (Coq, Lean, Isabelle, HOL Light), decision procedures, rewriting systems, type-theoretic reasoning engines, hybrid automated–interactive systems.
Formal Sciences	Logic	Model Theory	Structures, Languages & Interpretations	Languages, signatures, term algebras, formulas, structures, morphisms (homomorphisms/embeddings), definable sets/functions, elementary diagrams, substructures.
Formal Sciences	Logic	Model Theory	Satisfaction & Definability Theory	Formulas, terms, definable sets, definable relations, definable functions, satisfaction instances, types, definability classes (first-order, quantifier-free, etc.).
Formal Sciences	Logic	Model Theory	Quantifier Theory & Model Completeness	Quantifier classes (existential, universal, alternating), prenex classes, definability classes, model-complete theories, quantifier-eliminable theories, embeddings (strong, elementary).
Formal Sciences	Logic	Model Theory	Classification Theory	Stable theories, superstable theories, ω-stable theories, simple theories, NIP theories, NSOP theories, classifiable theories, o-minimal theories.
Formal Sciences	Logic	Model Theory	Tame / O-Minimal Model Theory	O-minimal structures, weakly o-minimal structures, expansions of real closed fields, definable manifolds, definable groups, definable equivalence classes, cell complexes.
Formal Sciences	Logic	Set Theory	Axiomatic Foundations & Cumulative Hierarchy	Ordinals, cardinals, stages of the hierarchy (V_\alpha), rank classes, definability tiers, combinatorial principles, transfinite recursion operators.
Formal Sciences	Logic	Set Theory	Constructibility & Inner Models	Levels of (L), admissible ordinals, fine-structural segments, premice, mice, sharps, core models, definability classes, iterable structures.
Formal Sciences	Logic	Set Theory	Large Cardinal Theory	Inaccessible, Mahlo, weakly compact, indescribable, measurable, supercompact, extendible, huge, superhuge, Reinhardt-like (when considering non–well-founded contexts).
Formal Sciences	Logic	Set Theory	Forcing & Independence Theory	Forcing notions (ccc, proper, semi-proper, closed, strategically closed), Boolean algebras, names, ground models, intermediate models, equivalence classes of forcing notions.
Formal Sciences	Logic	Set Theory	Descriptive Set Theory	Borel hierarchy, projective hierarchy, Wadge degrees, pointclasses (Σ, Π, Δ levels), equivalence relation complexity classes, definable sets under determinacy axioms.
Formal Sciences	Logic	Computability Theory	Models of Computation & Recursive Function Theory	Machine-based models (Turing machines, register machines), function-based models (primitive recursive, μ-recursive), term-rewriting models (λ-calculus, combinatory logic), oracle-augmented models, uniform vs. non-uniform models, deterministic vs. nondeterministic models.
Formal Sciences	Logic	Computability Theory	Recursively Enumerable (r.e.) Sets & Degrees	r.e. vs. co-r.e. sets, Turing degrees, many-one degrees, enumeration degrees, truth-table degrees, low/high degrees, minimal degrees, promptly simple sets, creative and productive sets, priority classes.
Formal Sciences	Logic	Computability Theory	Reducibility & Degrees of Unsolvability	Turing degrees, many-one degrees, truth-table and weak truth-table degrees, polynomial-time degrees (optionally), low/high degrees, minimal degrees, incomplete degrees, complete degrees, jump hierarchy categories.
Formal Sciences	Logic	Computability Theory	Arithmetical & Analytical Hierarchies	Arithmetical classes (Σₙ⁰, Πₙ⁰, Δₙ⁰), analytical classes (Σₙ¹, Πₙ¹, Δₙ¹), complete problems, relativized hierarchies (Σₙ⁰(A), Σₙ¹(A)), lightface vs. boldface distinctions, Borel and projective classes in extended settings.
Formal Sciences	Mathematics	Algebra	Group Theory	Finite groups, infinite groups, Abelian groups, non-Abelian groups, cyclic groups, permutation groups, matrix groups, Lie groups, free groups, simple groups, solvable groups, nilpotent groups, direct and semidirect products.
Formal Sciences	Mathematics	Algebra	Ring Theory	Commutative rings, noncommutative rings, integral domains, fields (as special rings), PIDs, UFDs, Noetherian rings, Artinian rings, matrix rings, polynomial rings, local rings, valuation rings, coordinate rings of algebraic varieties.
Formal Sciences	Mathematics	Algebra	Field Theory	Finite fields, number fields, function fields, algebraic extensions, transcendental extensions, separable and inseparable extensions, Galois extensions, local fields (e.g., ℚₚ), global fields (ℚ, function fields of curves), algebraically closed fields.
Formal Sciences	Mathematics	Algebra	Module Theory	Free modules, projective modules, injective modules, flat modules, torsion modules, finitely generated modules, Noetherian modules, Artinian modules, semisimple modules, simple modules, cyclic modules, tensor modules.
Formal Sciences	Mathematics	Algebra	Linear Algebra	Finite-dimensional vs infinite-dimensional vector spaces; Euclidean vs abstract vector spaces; inner-product spaces; normed spaces; orthogonal/unitary spaces; subspaces; direct sums; column/row spaces; eigenspaces; matrix algebras.
Formal Sciences	Mathematics	Algebra	Representation Theory	Representations of finite groups; Lie group/Lie algebra representations; modules over associative algebras; unitary representations; irreducible representations; reducible but indecomposable representations; semisimple categories; monoidal categories; tensor representations.
Formal Sciences	Mathematics	Algebra	Universal Algebra	Single-sorted vs multi-sorted algebras; varieties (HSP classes); quasivarieties; congruence-distributive/permutable algebras; clones; algebraic theories; term algebras; finitely generated vs infinitely generated algebras.
Formal Sciences	Mathematics	Algebra	Algebraic Combinatorics	Symmetric functions; representation-graded combinatorial structures; posets and lattices; association schemes; algebraic graph classes; Coxeter groups; matroids; hyperplane arrangements; combinatorial Hopf algebras; Schubert calculus; cluster combinatorics.
Formal Sciences	Mathematics	Mathematical Analysis	Real Analysis	Metric spaces, normed spaces, measurable spaces, Lebesgue spaces (Lᵖ), sets of finite/infinite measure, absolutely continuous functions, bounded variation functions, Cᵏ classes, improper integrals, convergence modes, compact sets.
Formal Sciences	Mathematics	Mathematical Analysis	Complex Analysis	Analytic vs non-analytic functions; entire functions; meromorphic functions; functions with isolated singularities; conformal mappings; harmonic functions; holomorphic families; power series representations; Laurent series; normal families.
Formal Sciences	Mathematics	Mathematical Analysis	Functional Analysis	Normed spaces, Banach spaces, Hilbert spaces, dual spaces, operator spaces (B(X), C*-algebras), locally convex spaces, distribution spaces, Sobolev spaces, compact operators, spectral classes, reflexive spaces, separable vs nonseparable spaces.
Formal Sciences	Mathematics	Mathematical Analysis	Harmonic Analysis	Fourier series; Fourier transforms; Lᵖ spaces; Hardy spaces (Hᵖ); BMO; Sobolev spaces; Calderón–Zygmund operators; singular integrals; maximal functions; Littlewood–Paley decompositions; representation-theoretic harmonic analysis on locally compact groups; wavelet systems.
Formal Sciences	Mathematics	Mathematical Analysis	Differential Equations (ODE/PDE)	ODEs (linear, nonlinear); autonomous vs non-autonomous systems; PDE classes (elliptic, parabolic, hyperbolic); boundary-value problems; initial-value problems; weak formulations; variational PDEs; spectral PDEs; systems of ODE/PDE; coupled field equations.
Formal Sciences	Mathematics	Geometry & Topology	Differential Geometry	Riemannian manifolds, pseudo-Riemannian manifolds, symplectic manifolds, smooth maps, vector bundles, principal bundles, differential forms, Lie groups and Lie algebras.
Formal Sciences	Mathematics	Geometry & Topology	Algebraic Geometry	Affine varieties, projective varieties, schemes, morphisms, divisors, line bundles, coherent sheaves, moduli spaces, birational classes, function fields.
Formal Sciences	Mathematics	Geometry & Topology	Metric Geometry	General metric spaces, geodesic spaces, CAT(0)/CAT(k) spaces, Alexandrov spaces, length spaces, metric graphs, ultrametric spaces, coarse-geometric classes (e.g., hyperbolic spaces).
Formal Sciences	Mathematics	Geometry & Topology	Point-Set Topology	Topological spaces, metric spaces, Hausdorff spaces, compact spaces, connected spaces, product spaces, quotient spaces, separable spaces, first/second countable spaces.
Formal Sciences	Mathematics	Geometry & Topology	Homotopy Theory	CW-complexes, path spaces, loop spaces ((\Omega X)), suspension spaces ((\Sigma X)), fibrations/cofibrations, homotopy categories, stable homotopy categories, spectra, pointed vs. unpointed spaces.
Formal Sciences	Mathematics	Geometry & Topology	Knot Theory	Prime knots, composite knots, alternating/non-alternating knots, torus knots, satellite knots, hyperbolic knots, tame vs. wild knots, oriented vs. unoriented knots.
Formal Sciences	Mathematics	Number Theory	Elementary Number Theory	Prime/composite numbers, congruence classes, multiplicative functions, arithmetic progressions, Diophantine types, residue systems.
Formal Sciences	Mathematics	Number Theory	Algebraic Number Theory	Global fields, local fields, Dedekind domains, ideal classes, Galois extensions, ramified/unramified extensions, completions at primes, algebraic integers.
Formal Sciences	Mathematics	Number Theory	Analytic Number Theory	L-functions, Dirichlet series, character sums, prime-counting functions, multiplicative functions, exponential sums, modular forms (in analytic context), zeta-type invariants.
Formal Sciences	Mathematics	Number Theory	Arithmetic Geometry	Rational points, integral points, local fields, global fields, abelian varieties, elliptic curves, curves of higher genus, arithmetic schemes, Selmer groups, Néron models, mod p reductions.
Formal Sciences	Mathematics	Number Theory	Modular and Automorphic Forms	Modular forms (holomorphic, Maass, cusp, Eisenstein), Hecke eigenforms, modular curves, automorphic forms on GL(n), automorphic representations, local factors of representations, adelic L-functions.
Formal Sciences	Mathematics	Number Theory	Transcendental Number Theory	Transcendental vs algebraic numbers; classes of special values (exponential, logarithmic, gamma values); Baker-type linear-form problems; Diophantine-approximation regimes; algebraic-independence hierarchies.
Social Sciences	Anthropology		Human Evolutionary Anthropology	Fossil species; anatomical regions; genetic markers; ecological zones; behavioral categories (foraging strategies, mating systems); adaptation types (physiological, anatomical, behavioral); cultural technologies that modify selection.
Social Sciences	Anthropology		Kinship, Descent & Domestic Organization	Kin types (consanguineal, affinal, fictive); descent systems (patrilineal, matrilineal, bilateral, ambilineal); residence patterns; marriage types (monogamy, polygyny, polyandry, levirate, sororate); household types (nuclear, extended, joint, stem); alliance structures; inheritance regimes.
Social Sciences	Anthropology		Ritual, Cultural Practice & Symbolic Systems	Ritual types (rites of passage, calendrical, healing, funerary, initiation, political); symbolic systems (cosmological, aesthetic, moral, classificatory); cultural practices (dance, art, taboo, sacrifice); semiotic domains (index, icon, symbol); performance genres; myth categories; embodied practices.
Social Sciences	Anthropology		Subsistence Systems, Environment & Human Adaptation	Subsistence modes (foraging, pastoralism, horticulture, fishing, agriculture); mobility types (nomadic, semi-sedentary, sedentary); ecological zones (savanna, forest, tundra, coastal, desert); technology classes (lithic, ceramic, agricultural, metallurgical); adaptive strategies (risk reduction, intensification, diversification); niche-construction activities.
Social Sciences	Anthropology		Material Culture, Technology & Archaeological Interpretation	Artifact types (lithics, ceramics, metalwork, textiles, architecture); technological systems (knapping, firing, metallurgy, weaving, construction); site types (habitation, ritual, workshop, quarry); depositional contexts (primary, secondary, mixed); interpretive frameworks (functional, stylistic, technological, behavioral).
Social Sciences	Anthropology		Ethnographic Method & Comparative Analysis	Fieldwork techniques (participant observation, interviews, mapping); ethnographic genres (life histories, thick description, narrative ethnography); comparative units (societies, cultural regions); coding types (behavioral, social, ritual, linguistic); analytic frameworks (structural, interpretive, cognitive, political-economic).
Social Sciences	Economics		Choice (Microeconomic Foundations)	Preferences (ordinal, cardinal, expected utility, prospect theory); technologies (production sets, cost functions); constraints (budget, time, information); decision environments (certainty, risk, uncertainty, dynamic programming); agent types (consumer, worker, firm).
Social Sciences	Economics		Interaction (Markets, Strategy & Mechanisms)	Market types (perfect competition, monopoly, oligopoly); game forms (normal form, extensive form); equilibrium types (Nash, subgame perfect, Bayesian Nash, Walrasian, correlated); mechanisms (auctions, matching, bargaining protocols, voting rules); environments (complete vs incomplete information).
Social Sciences	Economics		Aggregation & Dynamics (Macroeconomic Systems)	Growth models (Solow, endogenous growth); business-cycle models (RBC, New Keynesian); heterogeneous-agent macro models; overlapping-generations models; DSGE models; monetary policy rules; fiscal-policy frameworks; structural shocks; steady states vs transitional dynamics.
Social Sciences	Geography (Human)		Spatial Patterns & Spatial Analysis	Spatial forms (clustered, dispersed, random); spatial processes (diffusion, concentration, sprawl, segregation); spatial units (grids, administrative boundaries, census areas); spatial-analytic methods (GIS layers, spatial statistics, network models); regions (formal, functional, vernacular).
Social Sciences	Geography (Human)		Mobility, Flows & Connectivity	Types of mobility (daily, cyclical, seasonal, migratory, forced, voluntary); types of flows (people, goods, information, capital); network types (transport, communication, logistical); connectivity forms (hierarchical, decentralized, small-world, hub-and-spoke); mobility regimes (restrictive, permissive, mixed); diffusion patterns (contagious, network-based, hierarchical).
Social Sciences	Geography (Human)		Human–Environment Interaction & Landscape Modification	Land-use types (agricultural, pastoral, industrial, urban, forest); modification strategies (irrigation, terracing, burning, drainage, reforestation); hazard regimes (drought, flood, landslide, wildfire); socioecological systems (agrarian, urban, frontier, extractive); resource types (renewable, nonrenewable); feedback types (positive, negative, cascading).
Social Sciences	Geography (Human)		Place, Territory & Spatial Experience	Place types (home, sacred site, public square, memorial site); territory types (sovereign, communal, personal, claimed, contested); boundary types (formal, informal, symbolic, performative); experiential categories (embodiment, perception, sense of place, memory); spatial practices (movement, dwelling, marking, surveillance).
Social Sciences	Linguistics		Phonetics & Phonology	Consonants, vowels, phonemes, features, syllables (light/heavy), phonological processes (assimilation, deletion, insertion), tone and stress systems, prosodic constituents, distinctive feature sets.
Social Sciences	Linguistics		Morphology	Inflectional vs derivational morphology; free vs bound morphemes; prefixes/suffixes/infixes/circumfixes; root-and-pattern systems; agglutinative vs fusional vs isolating vs polysynthetic morphological types; morphological classes and declensions.
Social Sciences	Linguistics		Syntax	Phrase types, syntactic functions (subject, object), grammatical relations, movement types (A-movement, A’-movement), agreement systems, case systems, head-directionality types, configurational vs nonconfigurational languages.
Social Sciences	Linguistics		Semantics	Lexical meaning types; semantic roles (agent, theme, experiencer); predicate types (eventive, stative); quantifier classes; modality types; aspect classes; semantic features; type-theoretic categories.
Social Sciences	Linguistics		Pragmatics	Speech-act types (assertive, directive, commissive, expressive, declarative); implicature types (scalar, conventional, conversational); deixis types (person, place, time, discourse); presupposition triggers; discourse-relations; politeness strategies.
Social Sciences	Political Science		Political Institutions & Formal Political Order	Regime types (democratic, authoritarian, hybrid); constitutional forms (presidential, parliamentary, semi-presidential); electoral systems (majoritarian, proportional, mixed); legislatures (unicameral vs bicameral); courts (constitutional, supreme, administrative); bureaucratic systems (merit-based, patronage-based); federal vs unitary governance.
Social Sciences	Political Science		Political Behavior, Mobilization & Collective Action	Participation types (voting, protest, activism, volunteering); identities (ethnic, partisan, ideological, religious); mobilization forms (formal organizations, grassroots, digital activism); grievance-based vs opportunity-based collective action; conflict vs cooperation; persuasion vs polarization; mass movements vs small activist groups.
Social Sciences	Political Science		Governance, Policy Formation & State Capacity	Governance types (Weberian, clientelist, neopatrimonial); policy styles (consensual, adversarial, technocratic); policy instruments (regulation, taxation, subsidies, mandates, standards, public goods provision); state types (strong vs weak, centralized vs decentralized); capacity domains (coercive, administrative, fiscal, infrastructural).
Social Sciences	Political Science		International Relations & Global Order	System types (unipolar, bipolar, multipolar); conflict types (interstate war, civil war with external intervention, proxy conflict); cooperation types (treaties, alliances, institutions); actor types (great powers, middle powers, small states, non-state actors); regime types (trade, security, human rights, environment); interaction structures (anarchic, hierarchical, networked).
Social Sciences	Psychology		Cognitive Processes & Mental Architecture	Perceptual processes, attentional systems, memory subsystems (working, episodic, semantic, procedural), reasoning and inference systems, linguistic processors, executive-control structures, representational formats (symbolic vs. distributed).
Social Sciences	Psychology		Learning, Conditioning & Behavioral Mechanisms	Classical conditioning, operant conditioning, reinforcement schedules, extinction processes, discriminative control, stimulus generalization/discrimination, habit-formation mechanisms, behavioral shaping chains.
Social Sciences	Psychology		Emotion, Motivation & Affect Regulation	Basic emotions, complex emotions, intrinsic vs extrinsic motivation, appetitive vs aversive drives, automatic vs controlled regulation, cognitive reappraisal, suppression, avoidance, approach tendencies, mood states.
Social Sciences	Psychology		Development, Individual Differences & Psychometrics	Personality traits, cognitive abilities, developmental milestones, latent constructs, item types (binary, Likert, polytomous), factor models (1-factor, multi-factor, hierarchical), measurement models (IRT, CFA), growth-curve patterns.
Social Sciences	Sociology		Social Interaction Mechanisms	Social roles, identity categories, status positions (local), symbolic resources, interaction rituals, normative expectations, micro-power relations.
Social Sciences	Sociology		Social Structure Mechanisms	Social classes, castes, ethnic categories, gender categories, occupational strata, bureaucratic roles, institutional sectors, formal vs informal structures, status hierarchies, boundary-maintenance systems.
Social Sciences	Sociology		Social Network & Relational Dynamics	Ego networks, dyads, triads, clusters, components, cohesive subgroups, brokerage structures, structural holes, multiplex networks, temporal networks, directed/undirected networks.