A unital magma is a magma
(M,⋅) equipped with an identity element e∈M satisfying
e⋅a=a⋅e=afor all a∈M.
This is the weakest structure requiring an identity. All monoids
, loops
, and groups
are unital magmas.
Examples:
- Any monoid, loop, or group
- A set with a non-associative operation that still has an identity element