Theorem fnebas 32339

Description: A finer cover covers the same set as the original. (Contributed by Jeff Hankins, 28-Sep-2009.)

Hypotheses

Ref	Expression
fnebas.1	|- X = U. A
fnebas.2	|- Y = U. B

Assertion

Ref	Expression
fnebas	|- ( A Fne B -> X = Y )

Proof of Theorem fnebas

Step	Hyp	Ref	Expression
1		fnebas.1	. . 3 |- X = U. A
2		fnebas.2	. . 3 |- Y = U. B
3	1, 2	isfne4 32335	. 2 |- ( A Fne B <-> ( X = Y /\ A C_ ( topGen ` B ) ) )
4	3	simplbi 476	1 |- ( A Fne B -> X = Y )

Syntax hints:   -> wi 4   = wceq 1483   C_ wss 3574   U.cuni 4436   class class class wbr 4653   ` cfv 5888   topGenctg 16098   Fnecfne 32331

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-sbc 3436  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-br 4654  df-opab 4713  df-mpt 4730  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-iota 5851  df-fun 5890  df-fv 5896  df-topgen 16104  df-fne 32332

This theorem is referenced by:  fnetr  32346  fnessref  32352  fnemeet2  32362  fnejoin2  32364