Theorem exmo 1409

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 76	. . 3 |- (-. E.xph -> (E.xph -> E!xph))
2		df-mo 1376	. . 3 |- (E*xph <-> (E.xph -> E!xph))
3	1, 2	sylibr 200	. 2 |- (-. E.xph -> E*xph)
4	3	orri 231	1 |- (E.xph \/ E*xph)

Syntax hints:  -. wn 2   -> wi 3   \/ wo 222  E.wex 977  E!weu 1373  E*wmo 1374

This theorem is referenced by:  moexex 1431  mo2icl 1914  mosubopt 2793  dff2 3802  brdom3 4773

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 147  df-or 224  df-mo 1376

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