Theorem exmo 1812

Description: Something exists or at most one exists.

Assertion

Ref	Expression
exmo	|- (E.xph \/ E*xph)

Proof of Theorem exmo

Step	Hyp	Ref	Expression
1		pm2.21 92	. . 3 |- (-. E.xph -> (E.xph -> E!xph))
2		df-mo 1776	. . 3 |- (E*xph <-> (E.xph -> E!xph))
3	1, 2	sylibr 217	. 2 |- (-. E.xph -> E*xph)
4	3	orri 248	1 |- (E.xph \/ E*xph)

Syntax hints:  -. wn 2   -> wi 3   \/ wo 239  E.wex 1326  E!weu 1771  E*wmo 1772

This theorem is referenced by:  moexex 1841  mo2icl 2434  mosubopt 3551  dff3 4790  brdom3 5963  mof 14160

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 164  df-or 241  df-mo 1776

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