Theorem ax17el 2189

Description: Theorem to add distinct quantifier to atomic formula. This theorem demonstrates the induction basis for ax-17 1616 considered as a metatheorem.) (Contributed by NM, 5-Aug-1993.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
ax17el	|- (x e. y -> A.z x e. y)

Distinct variable groups:   x,z   y,z

Proof of Theorem ax17el

Step	Hyp	Ref	Expression
1		ax-15 2143	. 2 |- (-. A.z z = x -> (-. A.z z = y -> (x e. y -> A.z x e. y)))
2		ax-16 2144	. 2 |- (A.z z = x -> (x e. y -> A.z x e. y))
3		ax-16 2144	. 2 |- (A.z z = y -> (x e. y -> A.z x e. y))
4	1, 2, 3	pm2.61ii 157	1 |- (x e. y -> A.z x e. y)

Syntax hints:   -> wi 4  A.wal 1540

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-15 2143  ax-16 2144

This theorem is referenced by:  dveel2ALT  2191