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Model theory.

Model theory is the study of the relationship between formal theories (a collection of sentences in a formal language expressing statements about a mathematical structure), and their models (those structures in which the statements of the theory hold). The aspects investigated include the number and size of models of a theory, the relationship of different models to each other, and their interaction with the formal language itself. In particular, model theorists also investigate the sets that can be defined in a model of a theory, and the relationship of such definable sets to each other.

This category has the following 3 subcategories, out of 3 total.

- Model theorists (42 P)
- Nonstandard analysis (29 P)

The following 113 pages are in this category, out of 113 total. This list may not reflect recent changes.

- Satisfiability
- Saturated model
- Semantics of logic
- Signature (logic)
- Skolem normal form
- Skolem's paradox
- Soundness
- Spectrum of a theory
- Stability spectrum
- Stable group
- Stable model semantics
- Stable theory
- Strength (mathematical logic)
- Strongly minimal theory
- Structural Ramsey theory
- Structure (mathematical logic)
- Substructure (mathematics)