In mathematics, an identity element or neutral element of a binary operation is an element that leaves unchanged every element when the operation is applied. For example, 0 is an identity element of the addition of 展开

In the example S = {e,f} with the equalities given, S is a semigroup. It demonstrates the possibility for (S, ∗) to have several left identities. In fact, every element can be a left identity. In a similar … 展开

• Beauregard, Raymond A.; Fraleigh, John B. (1973), A First Course In Linear Algebra: with Optional Introduction to Groups, Rings, and Fields, … 展开

Let (S, ∗) be a set S equipped with a binary operation ∗. Then an element e of S is called a left identity if e ∗ s = s for all s in S, and a right identity if s ∗ e = s for all s in S. If e is both a left identity and a right identity, then it is called a two-sided identity, or simply an … 展开

• Absorbing element
• Additive inverse
• Generalized inverse
• Identity (equation)
• Identity function 展开

• M. Kilp, U. Knauer, A.V. Mikhalev, Monoids, Acts and Categories with Applications to Wreath Products and Graphs, De Gruyter … 展开