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Theorem unixp0im 4854
 Description: The union of an empty cross product is empty. (Contributed by Jim Kingdon, 18-Dec-2018.)
Assertion
Ref Expression
unixp0im ((𝐴 × 𝐵) = ∅ → (𝐴 × 𝐵) = ∅)

Proof of Theorem unixp0im
StepHypRef Expression
1 unieq 3589 . 2 ((𝐴 × 𝐵) = ∅ → (𝐴 × 𝐵) = ∅)
2 uni0 3607 . 2 ∅ = ∅
31, 2syl6eq 2088 1 ((𝐴 × 𝐵) = ∅ → (𝐴 × 𝐵) = ∅)
 Colors of variables: wff set class Syntax hints:   → wi 4   = wceq 1243  ∅c0 3224  ∪ cuni 3580   × cxp 4343 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022 This theorem depends on definitions:  df-bi 110  df-tru 1246  df-fal 1249  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-rex 2312  df-v 2559  df-dif 2920  df-in 2924  df-ss 2931  df-nul 3225  df-sn 3381  df-uni 3581 This theorem is referenced by: (None)
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