(mathematics) Preserving a specified property under transformation.

(algebra, representation theory) The branch of algebra concerned with actions of groups on algebraic varieties from the point of view of their effect on functions.

plural of invariable pendulum

A pendulum for carrying from station to station to be oscillated at each, so as to fix the relative acceleration of gravity.

(mathematics) Synonym of cumulant

(astronomy) The orbital plane passing through a planetary system's barycenter (center of mass) perpendicular to its angular momentum vector.

plural of invariable plane

(geometry) A certain invariant of complex projective surfaces.

(mathematics) A rational number that, in certain situations, counts pseudoholomorphic curves meeting prescribed conditions in a given symplectic manifold. They have applications in string theory.

(algebraic geometry) Given a compact moduli space of sheaves on a Calabi-Yau threefold, its Donaldson-Thomas invariant is the virtual number of its points, i.e., the integral of the cohomology class 1 against the virtual fundamental class.