Theorem 19.9v 1844

Description: Special case of Theorem 19.9 of [Margaris] p. 89. (Contributed by NM, 28-May-1995.) (Revised by NM, 21-May-2007.)

Assertion

Ref	Expression
19.9v	|- ( E. x ph <-> ph )

Distinct variable group:   ph, x

Proof of Theorem 19.9v

Step	Hyp	Ref	Expression
1		ax-17 1507	. 2 |- ( ph -> A. x ph )
2	1	19.9h 1623	1 |- ( E. x ph <-> ph )

Syntax hints:   <-> wb 104   E.wex 1469

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-4 1488  ax-17 1507

This theorem depends on definitions:  df-bi 116

This theorem is referenced by:  spc2gv  2780  spc3gv  2782  mo2icl  2867  brtpos2  6156