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Theorem inxp 4519
Description: The intersection of two cross products. Exercise 9 of [TakeutiZaring] p. 25. (Contributed by NM, 3-Aug-1994.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
Assertion
Ref Expression
inxp ((𝐴 × 𝐵) ∩ (𝐶 × 𝐷)) = ((𝐴𝐶) × (𝐵𝐷))

Proof of Theorem inxp
Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 inopab 4517 . . 3 ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}) = {⟨𝑥, 𝑦⟩ ∣ ((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷))}
2 an4 551 . . . . 5 (((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷)) ↔ ((𝑥𝐴𝑥𝐶) ∧ (𝑦𝐵𝑦𝐷)))
3 elin 3166 . . . . . 6 (𝑥 ∈ (𝐴𝐶) ↔ (𝑥𝐴𝑥𝐶))
4 elin 3166 . . . . . 6 (𝑦 ∈ (𝐵𝐷) ↔ (𝑦𝐵𝑦𝐷))
53, 4anbi12i 448 . . . . 5 ((𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷)) ↔ ((𝑥𝐴𝑥𝐶) ∧ (𝑦𝐵𝑦𝐷)))
62, 5bitr4i 185 . . . 4 (((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷)) ↔ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷)))
76opabbii 3866 . . 3 {⟨𝑥, 𝑦⟩ ∣ ((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷))} = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
81, 7eqtri 2103 . 2 ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}) = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
9 df-xp 4398 . . 3 (𝐴 × 𝐵) = {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)}
10 df-xp 4398 . . 3 (𝐶 × 𝐷) = {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}
119, 10ineq12i 3182 . 2 ((𝐴 × 𝐵) ∩ (𝐶 × 𝐷)) = ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)})
12 df-xp 4398 . 2 ((𝐴𝐶) × (𝐵𝐷)) = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
138, 11, 123eqtr4i 2113 1 ((𝐴 × 𝐵) ∩ (𝐶 × 𝐷)) = ((𝐴𝐶) × (𝐵𝐷))
Colors of variables: wff set class
Syntax hints:  wa 102   = wceq 1285  wcel 1434  cin 2982  {copab 3859   × cxp 4390
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 663  ax-5 1377  ax-7 1378  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-8 1436  ax-10 1437  ax-11 1438  ax-i12 1439  ax-bndl 1440  ax-4 1441  ax-14 1446  ax-17 1460  ax-i9 1464  ax-ial 1468  ax-i5r 1469  ax-ext 2065  ax-sep 3917  ax-pow 3969  ax-pr 3993
This theorem depends on definitions:  df-bi 115  df-3an 922  df-tru 1288  df-nf 1391  df-sb 1688  df-clab 2070  df-cleq 2076  df-clel 2079  df-nfc 2212  df-ral 2358  df-rex 2359  df-v 2612  df-un 2987  df-in 2989  df-ss 2996  df-pw 3403  df-sn 3423  df-pr 3424  df-op 3426  df-opab 3861  df-xp 4398  df-rel 4399
This theorem is referenced by:  xpindi  4520  xpindir  4521  dmxpinm  4605  xpssres  4694  xpdisj1  4798  xpdisj2  4799  imainrect  4817  xpima1  4818  xpima2m  4819  hashxp  9886
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