Theorem bnd 4206

Description: A very strong generalization of the Axiom of Replacement (compare zfrep6 4151). Its strength lies in the rather profound fact that ph ( x , y ) does not have to be a "function-like" wff, as it does in the standard Axiom of Replacement. This theorem is sometimes called the Boundedness Axiom. In the context of IZF, it is just a slight variation of ax-coll 4149. (Contributed by NM, 17-Oct-2004.)

Assertion

Ref	Expression
bnd	|- ( A. x e. z E. y ph -> E. w A. x e. z E. y e. w ph )

Distinct variable groups:   ph, z, w   x, y, z, w

Allowed substitution hints:   ph( x, y)

Proof of Theorem bnd

Step	Hyp	Ref	Expression
1		nfv 1542	. 2 |- F/ w ph
2	1	ax-coll 4149	1 |- ( A. x e. z E. y ph -> E. w A. x e. z E. y e. w ph )

Syntax hints:   -> wi 4   E.wex 1506   A.wral 2475   E.wrex 2476

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-gen 1463  ax-17 1540  ax-coll 4149

This theorem depends on definitions:  df-bi 117  df-nf 1475

This theorem is referenced by:  bnd2  4207