Metamath Proof Explorer


Theorem elfvexd

Description: If a function value has a member, then its argument is a set. Deduction form of elfvex . (An artifact of our function value definition.) (Contributed by David Moews, 1-May-2017)

Ref Expression
Hypothesis elfvexd.1 φABC
Assertion elfvexd φCV

Proof

Step Hyp Ref Expression
1 elfvexd.1 φABC
2 elfvex ABCCV
3 1 2 syl φCV