Semigroup: Difference between revisions

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{{magma property}}
==Definition==
==Definition==



Latest revision as of 22:59, 2 March 2010

This article defines a property that can be evaluated for a magma, and is invariant under isomorphisms of magmas.
View other such properties

Definition

QUICK PHRASES: set with associative binary operation, group without identity element and inverses

Symbol-free definition

A semigroup is a set equipped with an associative binary operation.

A semigroup need not have an identity element.

The definition of semigroup does not require it to be nonempty, so the empty set is a semigroup. However, some variants of the definition require a semigroup to be a nonempty set with an associative binary operation.