A finite integral domain is a field
Let
Proof
Let
be a nonzero, non-unity element of (if it is unity it is trivially a unit). Since is finite, there must exist some such that . By cancellation it follows and hence so is a unit.
It follows that
Let
Proof
Let
be a nonzero, non-unity element of (if it is unity it is trivially a unit). Since is finite, there must exist some such that . By cancellation it follows and hence so is a unit.
It follows that