Theorem moor 2108

Description: "At most one" is still the case when a disjunct is removed. (Contributed by NM, 5-Apr-2004.)

Assertion

Ref	Expression
moor	|- ( E* x ( ph \/ ps ) -> E* x ph )

Proof of Theorem moor

Step	Hyp	Ref	Expression
1		orc 713	. 2 |- ( ph -> ( ph \/ ps ) )
2	1	moimi 2102	1 |- ( E* x ( ph \/ ps ) -> E* x ph )

Syntax hints:   -> wi 4   \/ wo 709   E*wmo 2038

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1457  ax-7 1458  ax-gen 1459  ax-ie1 1503  ax-ie2 1504  ax-8 1514  ax-10 1515  ax-11 1516  ax-i12 1517  ax-bndl 1519  ax-4 1520  ax-17 1536  ax-i9 1540  ax-ial 1544  ax-i5r 1545

This theorem depends on definitions:  df-bi 117  df-nf 1471  df-sb 1773  df-eu 2040  df-mo 2041

This theorem is referenced by:  mooran2  2110