unital
Adjective
Meaning
unital (not comparable)
(mathematics) (of an algebra) containing a multiplicative identity element (or unit), i.e. an element 1 with the property 1x = x1 = x for all elements x of the algebra.
Synonyms
Phrases with the word
Anagrams
Examples
Example The 2 2-matrices over the reals form a unital algebra in the obvious way.
Formal definitions In a unital magma Let be a set closed under a binary operation (i.
If rings are not required to be unital, the last condition is omitted.
In a unital alternative algebra, multiplicative inverses are unique whenever they exist.
In fact the converse is also true and this gives a characterization of division rings via their module category: A unital ring R is a division ring if and only if every R- module is free Grillet, Pierre Antoine.
In other words, in a monoid (an associative unital magma) every element has at most one inverse (as defined in this section).