Theorem qexmid 1121

Description: Quantified "excluded middle." Exercise 9.2a of Boolos, p. 111, Computability and Logic.

Assertion

Ref	Expression
qexmid	|- E.x(ph -> A.xph)

Proof of Theorem qexmid

Step	Hyp	Ref	Expression
1		19.8a 1029	. 2 |- (A.xph -> E.xA.xph)
2	1	19.35ri 1077	1 |- E.x(ph -> A.xph)

Syntax hints:   -> wi 3  A.wal 954  E.wex 980

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-gen 963  ax-4 973  ax-5o 975

This theorem depends on definitions:  df-bi 147  df-an 225  df-ex 981

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