Theorem nexr 2062

Description: Inference associated with the contrapositive of 19.8a 2052. (Contributed by Jeff Hankins, 26-Jul-2009.)

Hypothesis

Ref	Expression
nexr.1	|- -. E. x ph

Assertion

Ref	Expression
nexr	|- -. ph

Proof of Theorem nexr

Step	Hyp	Ref	Expression
1		nexr.1	. 2 |- -. E. x ph
2		19.8a 2052	. 2 |- ( ph -> E. x ph )
3	1, 2	mto 188	1 |- -. ph

Syntax hints:   -. wn 3   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-12 2047

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

This theorem is referenced by:  alimp-surprise  42526