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Theorem inxp 4677
 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 4675 . . 3 ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}) = {⟨𝑥, 𝑦⟩ ∣ ((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷))}
2 an4 576 . . . . 5 (((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷)) ↔ ((𝑥𝐴𝑥𝐶) ∧ (𝑦𝐵𝑦𝐷)))
3 elin 3260 . . . . . 6 (𝑥 ∈ (𝐴𝐶) ↔ (𝑥𝐴𝑥𝐶))
4 elin 3260 . . . . . 6 (𝑦 ∈ (𝐵𝐷) ↔ (𝑦𝐵𝑦𝐷))
53, 4anbi12i 456 . . . . 5 ((𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷)) ↔ ((𝑥𝐴𝑥𝐶) ∧ (𝑦𝐵𝑦𝐷)))
62, 5bitr4i 186 . . . 4 (((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷)) ↔ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷)))
76opabbii 3999 . . 3 {⟨𝑥, 𝑦⟩ ∣ ((𝑥𝐴𝑦𝐵) ∧ (𝑥𝐶𝑦𝐷))} = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
81, 7eqtri 2161 . 2 ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}) = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
9 df-xp 4549 . . 3 (𝐴 × 𝐵) = {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)}
10 df-xp 4549 . . 3 (𝐶 × 𝐷) = {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)}
119, 10ineq12i 3276 . 2 ((𝐴 × 𝐵) ∩ (𝐶 × 𝐷)) = ({⟨𝑥, 𝑦⟩ ∣ (𝑥𝐴𝑦𝐵)} ∩ {⟨𝑥, 𝑦⟩ ∣ (𝑥𝐶𝑦𝐷)})
12 df-xp 4549 . 2 ((𝐴𝐶) × (𝐵𝐷)) = {⟨𝑥, 𝑦⟩ ∣ (𝑥 ∈ (𝐴𝐶) ∧ 𝑦 ∈ (𝐵𝐷))}
138, 11, 123eqtr4i 2171 1 ((𝐴 × 𝐵) ∩ (𝐶 × 𝐷)) = ((𝐴𝐶) × (𝐵𝐷))
 Colors of variables: wff set class Syntax hints:   ∧ wa 103   = wceq 1332   ∈ wcel 1481   ∩ cin 3071  {copab 3992   × cxp 4541 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-10 1484  ax-11 1485  ax-i12 1486  ax-bndl 1487  ax-4 1488  ax-14 1493  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122  ax-sep 4050  ax-pow 4102  ax-pr 4135 This theorem depends on definitions:  df-bi 116  df-3an 965  df-tru 1335  df-nf 1438  df-sb 1737  df-clab 2127  df-cleq 2133  df-clel 2136  df-nfc 2271  df-ral 2422  df-rex 2423  df-v 2689  df-un 3076  df-in 3078  df-ss 3085  df-pw 3513  df-sn 3534  df-pr 3535  df-op 3537  df-opab 3994  df-xp 4549  df-rel 4550 This theorem is referenced by:  xpindi  4678  xpindir  4679  dmxpin  4765  xpssres  4858  xpdisj1  4967  xpdisj2  4968  imainrect  4988  xpima1  4989  xpima2m  4990  hashxp  10600  txbas  12457  txrest  12475  metreslem  12579
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