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Theorem xpen 6055
Description: Equinumerosity law for cross product. Proposition 4.22(b) of [Mendelson] p. 254. (Contributed by set.mm contributors, 24-Jul-2004.) (Revised by set.mm contributors, 9-Mar-2013.)
Assertion
Ref Expression
xpen ((AB CD) → (A × C) ≈ (B × D))

Proof of Theorem xpen
Dummy variables f g are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 bren 6030 . . . 4 (ABf f:A1-1-ontoB)
2 bren 6030 . . . 4 (CDg g:C1-1-ontoD)
31, 2anbi12i 678 . . 3 ((AB CD) ↔ (f f:A1-1-ontoB g g:C1-1-ontoD))
4 eeanv 1913 . . 3 (fg(f:A1-1-ontoB g:C1-1-ontoD) ↔ (f f:A1-1-ontoB g g:C1-1-ontoD))
53, 4bitr4i 243 . 2 ((AB CD) ↔ fg(f:A1-1-ontoB g:C1-1-ontoD))
6 f1opprod 5844 . . . 4 ((f:A1-1-ontoB g:C1-1-ontoD) → PProd (f, g):(A × C)–1-1-onto→(B × D))
7 vex 2862 . . . . . 6 f V
8 vex 2862 . . . . . 6 g V
97, 8pprodex 5838 . . . . 5 PProd (f, g) V
109f1oen 6033 . . . 4 ( PProd (f, g):(A × C)–1-1-onto→(B × D) → (A × C) ≈ (B × D))
116, 10syl 15 . . 3 ((f:A1-1-ontoB g:C1-1-ontoD) → (A × C) ≈ (B × D))
1211exlimivv 1635 . 2 (fg(f:A1-1-ontoB g:C1-1-ontoD) → (A × C) ≈ (B × D))
135, 12sylbi 187 1 ((AB CD) → (A × C) ≈ (B × D))
Colors of variables: wff setvar class
Syntax hints:  wi 4   wa 358  wex 1541   class class class wbr 4639   × cxp 4770  1-1-ontowf1o 4780   PProd cpprod 5737  cen 6028
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-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4078  ax-xp 4079  ax-cnv 4080  ax-1c 4081  ax-sset 4082  ax-si 4083  ax-ins2 4084  ax-ins3 4085  ax-typlower 4086  ax-sn 4087
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-ne 2518  df-ral 2619  df-rex 2620  df-reu 2621  df-rmo 2622  df-rab 2623  df-v 2861  df-sbc 3047  df-nin 3211  df-compl 3212  df-in 3213  df-un 3214  df-dif 3215  df-symdif 3216  df-ss 3259  df-pss 3261  df-nul 3551  df-if 3663  df-pw 3724  df-sn 3741  df-pr 3742  df-uni 3892  df-int 3927  df-opk 4058  df-1c 4136  df-pw1 4137  df-uni1 4138  df-xpk 4185  df-cnvk 4186  df-ins2k 4187  df-ins3k 4188  df-imak 4189  df-cok 4190  df-p6 4191  df-sik 4192  df-ssetk 4193  df-imagek 4194  df-idk 4195  df-iota 4339  df-0c 4377  df-addc 4378  df-nnc 4379  df-fin 4380  df-lefin 4440  df-ltfin 4441  df-ncfin 4442  df-tfin 4443  df-evenfin 4444  df-oddfin 4445  df-sfin 4446  df-spfin 4447  df-phi 4565  df-op 4566  df-proj1 4567  df-proj2 4568  df-opab 4623  df-br 4640  df-1st 4723  df-swap 4724  df-co 4726  df-ima 4727  df-id 4767  df-xp 4784  df-cnv 4785  df-rn 4786  df-dm 4787  df-fun 4789  df-fn 4790  df-f 4791  df-f1 4792  df-fo 4793  df-f1o 4794  df-2nd 4797  df-txp 5736  df-pprod 5738  df-en 6029
This theorem is referenced by:  mucnc  6131
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