Theorem 19.9v 1806

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 1471	. 2 |- ( ph -> A. x ph )
2	1	19.9h 1586	1 |- ( E. x ph <-> ph )

Syntax hints:   <-> wb 104   E.wex 1433

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-gen 1390  ax-ie1 1434  ax-ie2 1435  ax-4 1452  ax-17 1471

This theorem depends on definitions:  df-bi 116

This theorem is referenced by:  spc2gv  2723  spc3gv  2725  mo2icl  2808  brtpos2  6054