Theorem funoprab

Description: "At most one" is a sufficient condition for an operation class abstraction to be a function. (Contributed by NM, 17-Mar-1995)

	Ref	Expression
Hypothesis	funoprab.1	|- E* z ph
Assertion	funoprab	|- Fun { <. <. x , y >. , z >. | ph }

Proof

Step	Hyp	Ref	Expression
1		funoprab.1	|- E* z ph
2	1	gen2	|- A. x A. y E* z ph
3		funoprabg	|- ( A. x A. y E* z ph -> Fun { <. <. x , y >. , z >. | ph } )
4	2 3	ax-mp	|- Fun { <. <. x , y >. , z >. | ph }