Theorem uniabio 4349

Description: Part of Theorem 8.17 in [Quine] p. 56. This theorem serves as a lemma for the fundamental property of iota. (Contributed by Andrew Salmon, 11-Jul-2011.)

Assertion

Ref	Expression
uniabio	|- (A.x(ph <-> x = y) -> U.{x | ph} = y)

Distinct variable group:   x,y

Allowed substitution hints:   ph(x,y)

Proof of Theorem uniabio

Step	Hyp	Ref	Expression
1		abbi 2463	. . . . 5 |- (A.x(ph <-> x = y) <-> {x | ph} = {x | x = y})
2	1	biimpi 186	. . . 4 |- (A.x(ph <-> x = y) -> {x | ph} = {x | x = y})
3		df-sn 3741	. . . 4 |- {y} = {x | x = y}
4	2, 3	syl6eqr 2403	. . 3 |- (A.x(ph <-> x = y) -> {x | ph} = {y})
5	4	unieqd 3902	. 2 |- (A.x(ph <-> x = y) -> U.{x | ph} = U.{y})
6		vex 2862	. . 3 |- y e. _V
7	6	unisn 3907	. 2 |- U.{y} = y
8	5, 7	syl6eq 2401	1 |- (A.x(ph <-> x = y) -> U.{x | ph} = y)

Syntax hints:   -> wi 4   <-> wb 176  A.wal 1540   = wceq 1642  {cab 2339  {csn 3737  U.cuni 3891

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-rex 2620  df-v 2861  df-nin 3211  df-compl 3212  df-un 3214  df-sn 3741  df-pr 3742  df-uni 3892

This theorem is referenced by:  iotaval  4350  iotauni  4351