Definition of idempotents:
(adj) :
(mathematics, computing) (said of a function) Such that, when performed multiple times on the same subject, it has no further effect on its subject after the first time it is performed.
(adj) :
(mathematics) (said of an element of an algebraic structure with a binary operation, such as a group or semigroup) Such that, when it operates on itself, the result is equal to itself.
(adj) :
(mathematics) (said of a binary operation) Such that all of the distinct elements it can operate on are idempotent (in the sense given just above).
(adj) :
(mathematics) (said of an algebraic structure) Having an idempotent operation (in the sense given above).
(n) :
(mathematics) An idempotent element.
(n) :
(mathematics) An idempotent structure.