Theorem mo4f 1395

Description: "At most one" expressed using implicit substitution.

Hypotheses

Ref	Expression
mo4f.1	|- (ps -> A.xps)
mo4f.2	|- (x = y -> (ph <-> ps))

Assertion

Ref	Expression
mo4f	|- (E*xph <-> A.xA.y((ph /\ ps) -> x = y))

Distinct variable groups:   x,y   ph,y

Proof of Theorem mo4f

Step	Hyp	Ref	Expression
1		ax-17 968	. . 3 |- (ph -> A.yph)
2	1	mo3 1394	. 2 |- (E*xph <-> A.xA.y((ph /\ [y / x]ph) -> x = y))
3		mo4f.1	. . . . . 6 |- (ps -> A.xps)
4		mo4f.2	. . . . . 6 |- (x = y -> (ph <-> ps))
5	3, 4	sbie 1192	. . . . 5 |- ([y / x]ph <-> ps)
6	5	anbi2i 479	. . . 4 |- ((ph /\ [y / x]ph) <-> (ph /\ ps))
7	6	imbi1i 186	. . 3 |- (((ph /\ [y / x]ph) -> x = y) <-> ((ph /\ ps) -> x = y))
8	7	2albii 997	. 2 |- (A.xA.y((ph /\ [y / x]ph) -> x = y) <-> A.xA.y((ph /\ ps) -> x = y))
9	2, 8	bitr 173	1 |- (E*xph <-> A.xA.y((ph /\ ps) -> x = y))

Syntax hints:   -> wi 3   <-> wb 146   /\ wa 223  A.wal 951   = wceq 953  E*wmo 1374

This theorem is referenced by:  mo4 1396  moi 1915  moop2 2790

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 959  ax-gen 960  ax-8 961  ax-10 963  ax-11 964  ax-12 965  ax-17 968  ax-4 970  ax-5o 972  ax-6o 975  ax-9o 1119  ax-10o 1136  ax-16 1206  ax-11o 1213

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-ex 978  df-sb 1168  df-eu 1375  df-mo 1376

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