Theorem notzfaus 4577

Description: In the Separation Scheme zfauscl 4526, we require that y not occur in ph (which can be generalized to "not be free in"). Here we show special cases of A and ph that result in a contradiction by violating this requirement. (Contributed by NM, 8-Feb-2006.)

Hypotheses

Ref	Expression
notzfaus.1	|- A = { (/) }
notzfaus.2	|- ( ph <-> -. x e. y )

Assertion

Ref	Expression
notzfaus	|- -. E. y A. x ( x e. y <-> ( x e. A /\ ph ) )

Distinct variable group:   x, A

Allowed substitution hints:   ph( x, y)   A( y)

Proof of Theorem notzfaus

Step	Hyp	Ref	Expression
1		notzfaus.1	. . . . . 6 |- A = { (/) }
2		0ex 4534	. . . . . . 7 |- (/) e. _V
3	2	snnz 4089	. . . . . 6 |- { (/) } =/= (/)
4	1, 3	eqnetri 2693	. . . . 5 |- A =/= (/)
5		n0 3740	. . . . 5 |- ( A =/= (/) <-> E. x x e. A )
6	4, 5	mpbi 212	. . . 4 |- E. x x e. A
7		biimt 337	. . . . . 6 |- ( x e. A -> ( x e. y <-> ( x e. A -> x e. y ) ) )
8		iman 426	. . . . . . 7 |- ( ( x e. A -> x e. y ) <-> -. ( x e. A /\ -. x e. y ) )
9		notzfaus.2	. . . . . . . 8 |- ( ph <-> -. x e. y )
10	9	anbi2i 699	. . . . . . 7 |- ( ( x e. A /\ ph ) <-> ( x e. A /\ -. x e. y ) )
11	8, 10	xchbinxr 313	. . . . . 6 |- ( ( x e. A -> x e. y ) <-> -. ( x e. A /\ ph ) )
12	7, 11	syl6bb 265	. . . . 5 |- ( x e. A -> ( x e. y <-> -. ( x e. A /\ ph ) ) )
13		xor3 359	. . . . 5 |- ( -. ( x e. y <-> ( x e. A /\ ph ) ) <-> ( x e. y <-> -. ( x e. A /\ ph ) ) )
14	12, 13	sylibr 216	. . . 4 |- ( x e. A -> -. ( x e. y <-> ( x e. A /\ ph ) ) )
15	6, 14	eximii 1708	. . 3 |- E. x -. ( x e. y <-> ( x e. A /\ ph ) )
16		exnal 1698	. . 3 |- ( E. x -. ( x e. y <-> ( x e. A /\ ph ) ) <-> -. A. x ( x e. y <-> ( x e. A /\ ph ) ) )
17	15, 16	mpbi 212	. 2 |- -. A. x ( x e. y <-> ( x e. A /\ ph ) )
18	17	nex 1677	1 |- -. E. y A. x ( x e. y <-> ( x e. A /\ ph ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 188   /\ wa 371   A.wal 1441   = wceq 1443   E.wex 1662   e. wcel 1886   =/= wne 2621   (/)c0 3730   {csn 3967

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1668  ax-4 1681  ax-5 1757  ax-6 1804  ax-7 1850  ax-10 1914  ax-11 1919  ax-12 1932  ax-13 2090  ax-ext 2430  ax-nul 4533

This theorem depends on definitions:  df-bi 189  df-or 372  df-an 373  df-tru 1446  df-ex 1663  df-nf 1667  df-sb 1797  df-clab 2437  df-cleq 2443  df-clel 2446  df-nfc 2580  df-ne 2623  df-v 3046  df-dif 3406  df-nul 3731  df-sn 3968

This theorem is referenced by: (None)