Invariant

Invariant and invariance may have several meanings, among which are:

Computer science

• Invariant (computer science), an Expression whose value doesn't change during program execution
• A type in overriding that is neither covariant nor contravariant
• Class invariant, invariants used to constrain objects of a class
• Loop invariant, invariants used to prove properties of loops

Other uses

• Invariant (mathematics), something unaltered by a transformation, for example: taking a homotopy group functor on the category of topological spaces. Then, homeomorphic spaces have isomorphic fundamental group. See topological invariant.
• Invariant (music)
• Invariant (physics), meaning that something does not change under a transformation, such as from one reference frame to another
• Writer invariant, property of a text which is similar in all texts of a given author, and different in texts of different authors
• Invariance (magazine), a French Communist journal
• The Invariant Society, the Oxford student mathematics society