Metamath Proof Explorer


Theorem moexexvw

Description: "At most one" double quantification. Version of moexexv with an additional disjoint variable condition, which does not require ax-13 . (Contributed by NM, 26-Jan-1997) (Revised by Gino Giotto, 22-Aug-2023) Factor out common proof lines with moexex . (Revised by Wolf Lammen, 2-Oct-2023)

Ref Expression
Assertion moexexvw
|- ( ( E* x ph /\ A. x E* y ps ) -> E* y E. x ( ph /\ ps ) )

Proof

Step Hyp Ref Expression
1 nfv
 |-  F/ y ph
2 nfv
 |-  F/ y E* x ph
3 nfe1
 |-  F/ x E. x ( ph /\ ps )
4 3 nfmov
 |-  F/ x E* y E. x ( ph /\ ps )
5 1 2 4 moexexlem
 |-  ( ( E* x ph /\ A. x E* y ps ) -> E* y E. x ( ph /\ ps ) )