Theorem sq1

Description: The square of 1 is 1. (Contributed by NM, 22-Aug-1999)

	Ref	Expression
Assertion	sq1	$$⊢1^2=1$$

Proof

Step	Hyp	Ref	Expression
1		2z	$$⊢2\in \mathbb{Z}$$
2		1exp	$$⊢2\in \mathbb{Z}\to 1^2=1$$
3	1 2	ax-mp	$$⊢1^2=1$$