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Theorem bj-eldiag2 37120
Description: Characterization of the elements of the diagonal of a Cartesian square. Subsumed by bj-elid7 37114. (Contributed by BJ, 22-Jun-2019.)
Assertion
Ref Expression
bj-eldiag2 (𝐴𝑉 → (⟨𝐵, 𝐶⟩ ∈ (Id‘𝐴) ↔ (𝐵𝐴𝐵 = 𝐶)))

Proof of Theorem bj-eldiag2
StepHypRef Expression
1 bj-diagval2 37118 . . 3 (𝐴𝑉 → (Id‘𝐴) = ( I ∩ (𝐴 × 𝐴)))
21eleq2d 2823 . 2 (𝐴𝑉 → (⟨𝐵, 𝐶⟩ ∈ (Id‘𝐴) ↔ ⟨𝐵, 𝐶⟩ ∈ ( I ∩ (𝐴 × 𝐴))))
3 elin 3979 . . 3 (⟨𝐵, 𝐶⟩ ∈ ( I ∩ (𝐴 × 𝐴)) ↔ (⟨𝐵, 𝐶⟩ ∈ I ∧ ⟨𝐵, 𝐶⟩ ∈ (𝐴 × 𝐴)))
4 bj-opelidb1 37096 . . . 4 (⟨𝐵, 𝐶⟩ ∈ I ↔ (𝐵 ∈ V ∧ 𝐵 = 𝐶))
5 opelxp 5720 . . . 4 (⟨𝐵, 𝐶⟩ ∈ (𝐴 × 𝐴) ↔ (𝐵𝐴𝐶𝐴))
64, 5anbi12i 627 . . 3 ((⟨𝐵, 𝐶⟩ ∈ I ∧ ⟨𝐵, 𝐶⟩ ∈ (𝐴 × 𝐴)) ↔ ((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)))
7 simprl 770 . . . . 5 (((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)) → 𝐵𝐴)
8 simplr 768 . . . . 5 (((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)) → 𝐵 = 𝐶)
97, 8jca 511 . . . 4 (((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)) → (𝐵𝐴𝐵 = 𝐶))
10 elex 3498 . . . . . 6 (𝐵𝐴𝐵 ∈ V)
1110anim1i 614 . . . . 5 ((𝐵𝐴𝐵 = 𝐶) → (𝐵 ∈ V ∧ 𝐵 = 𝐶))
12 eleq1 2825 . . . . . . 7 (𝐵 = 𝐶 → (𝐵𝐴𝐶𝐴))
1312biimpcd 249 . . . . . 6 (𝐵𝐴 → (𝐵 = 𝐶𝐶𝐴))
1413imdistani 568 . . . . 5 ((𝐵𝐴𝐵 = 𝐶) → (𝐵𝐴𝐶𝐴))
1511, 14jca 511 . . . 4 ((𝐵𝐴𝐵 = 𝐶) → ((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)))
169, 15impbii 209 . . 3 (((𝐵 ∈ V ∧ 𝐵 = 𝐶) ∧ (𝐵𝐴𝐶𝐴)) ↔ (𝐵𝐴𝐵 = 𝐶))
173, 6, 163bitri 297 . 2 (⟨𝐵, 𝐶⟩ ∈ ( I ∩ (𝐴 × 𝐴)) ↔ (𝐵𝐴𝐵 = 𝐶))
182, 17bitrdi 287 1 (𝐴𝑉 → (⟨𝐵, 𝐶⟩ ∈ (Id‘𝐴) ↔ (𝐵𝐴𝐵 = 𝐶)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 206  wa 395   = wceq 1535  wcel 2104  Vcvv 3477  cin 3962  cop 4637   I cid 5576   × cxp 5682  cfv 6559  Idcdiag2 37115
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1963  ax-7 2003  ax-8 2106  ax-9 2114  ax-10 2137  ax-11 2153  ax-12 2173  ax-ext 2704  ax-sep 5301  ax-nul 5308  ax-pow 5367  ax-pr 5431  ax-un 7748
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 847  df-3an 1087  df-tru 1538  df-fal 1548  df-ex 1775  df-nf 1779  df-sb 2061  df-mo 2536  df-eu 2565  df-clab 2711  df-cleq 2725  df-clel 2812  df-nfc 2888  df-ral 3058  df-rex 3067  df-rab 3433  df-v 3479  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-pw 4607  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4916  df-br 5151  df-opab 5213  df-mpt 5234  df-id 5577  df-xp 5690  df-rel 5691  df-cnv 5692  df-co 5693  df-dm 5694  df-res 5696  df-iota 6511  df-fun 6561  df-fv 6567  df-bj-diag 37116
This theorem is referenced by: (None)
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