(physics) A type of field theory in which the Lagrangian is invariant under a continuous group of local transformations.

(political science, sociology) Any theory that centres its gaze, analysis, and interpretation around human action. E.g. rational choice theory, phenomenology, etc.

Ideas that are not supported by mainstream scholarship.

(grammar) The original Chomskyan model of generative grammar, based around two different representations of a sentence (deep structure and surface structure) linked by transformational grammar.

Synonym of white replacement theory.

(mathematics, number theory) The branch of number theory in which number-theoretic questions are expressed in terms of properties of algebraic number fields or related objects, and studied using techniques from algebra.

(astronomy) A mathematical theory that attempts to describe the evolution of the constituents of the universe following the Big Bang

the theory that changes in prices and the value of money vary with changes in the amount of money in circulation

(physics) A theory that unifies the electromagnetic interaction, the weak interaction, and the strong interaction.

(chemistry, physics) a theory, a combination of the earlier crystal field theory with molecular orbital theory, that describes the structure of coordination compounds