Theorem bj-evalfn

Description: The evaluation at a class is a function on the universal class. (General form of slotfn ). (Contributed by Mario Carneiro, 22-Sep-2015) (Revised by BJ, 27-Dec-2021)

	Ref	Expression
Assertion	bj-evalfn	|- Slot A Fn _V

Proof

Step	Hyp	Ref	Expression
1		fvex	|- ( f ` A ) e. _V
2		df-slot	|- Slot A = ( f e. _V |-> ( f ` A ) )
3	1 2	fnmpti	|- Slot A Fn _V