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Cancellative commutative semigroups
Abbreviation: CanCSgrp
Definition
A \emph{cancellative commutative semigroup} is a commutative semigroup S=⟨S,⋅⟩ such that
⋅ is \emph{cancellative}: x⋅z=y⋅z⟹x=y
Morphisms
Let S and T be cancellative commutative semigroups. A morphism from S to T is a function h:S→T that is a homomorphism:
h(xy)=h(x)h(y)
Examples
Example 1: ⟨N,+⟩, the natural numbers, with additition.
Basic results
Properties
Finite members
f(1)=1f(2)=f(3)=f(4)=f(5)=f(6)=f(7)=