Identity element
Concept history
A revision trail for this concept page.
Revision 767
7/31/2026, 3:21:50 PM · Sequoia
Concept edited
Recorded titleIdentity element
Recorded typeDefinition
Compare with revision 7621 changed line
1
Given a [[Magma|magma]] $(M,*)$, an element $e$ is an identity element if, for all $x$ in $M$,2
$$e*x=x*e=x.$$3
Forcefully, if an identity element exists, it has to be unique.3
4
##### Remarks5
- A magma with an identity element is called [[unital|unital magma]].Revision 762
7/31/2026, 1:36:13 PM · Ancient Tree
Concept edited
This older revision predates detailed metadata tracking.
Revision 761
7/31/2026, 1:33:27 PM · Ancient Tree
Concept edited
Compare with revision 7573 changed lines
1
Given a [[Magma|magma]] $(M,*)$, an element $e$ is an identity element if, for all $x$ in $M$,2
$$e*x=x*e=x.$$3
4
##### Remarks5
- A magma with an identity element is called [[unital|unital magma]].Revision 757
7/31/2026, 1:24:18 PM · Ancient Tree
Concept created
Given a [[Magma|magma]] $(M,*)$, an element $e$ is an identity element if, for all $x$ in $M$, $$e*x=x*e=x.$$