Theorem 19.9hOLD 2206

Description: Obsolete proof of 19.9h 2120 as of 6-Oct-2021. (Contributed by FL, 24-Mar-2007.) (Proof shortened by Wolf Lammen, 5-Jan-2018.) (Proof shortened by Wolf Lammen, 14-Jul-2020.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypothesis

Ref	Expression
19.9hOLD.1	|- ( ph -> A. x ph )

Assertion

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

Proof of Theorem 19.9hOLD

Step	Hyp	Ref	Expression
1		19.9hOLD.1	. . 3 |- ( ph -> A. x ph )
2	1	nfiOLD 1734	. 2 |- F/ x ph
3	2	19.9OLD 2205	1 |- ( E. x ph <-> ph )

Syntax hints:   -> wi 4   <-> wb 196   A.wal 1481   E.wex 1704

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-10 2019  ax-12 2047

This theorem depends on definitions:  df-bi 197  df-ex 1705  df-nfOLD 1721

This theorem is referenced by: (None)