# Binary operation on magma determines neutral element

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Revision as of 21:46, 31 July 2008 by Vipul (talk | contribs) (New page: ==Statement== Suppose <math>(S,*)</math> is a magma (set <math>S</math> with associative binary operation <math>*</math>). Then, if there exists a neutral element for <math>*</mat...)

## Statement

Suppose is a magma (set with associative binary operation ). Then, if there exists a neutral element for (i.e., an element such that for all ), the element is uniquely determined by .

In other words, a magma can have at most one two-sided neutral element.