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Theorem bj-elid6 36706
Description: Characterization of the elements of the diagonal of a Cartesian square. (Contributed by BJ, 22-Jun-2019.)
Assertion
Ref Expression
bj-elid6 (𝐵 ∈ ( I ↾ 𝐴) ↔ (𝐵 ∈ (𝐴 × 𝐴) ∧ (1st𝐵) = (2nd𝐵)))

Proof of Theorem bj-elid6
StepHypRef Expression
1 df-res 5684 . . . 4 ( I ↾ 𝐴) = ( I ∩ (𝐴 × V))
21elin2 4191 . . 3 (𝐵 ∈ ( I ↾ 𝐴) ↔ (𝐵 ∈ I ∧ 𝐵 ∈ (𝐴 × V)))
32biancomi 461 . 2 (𝐵 ∈ ( I ↾ 𝐴) ↔ (𝐵 ∈ (𝐴 × V) ∧ 𝐵 ∈ I ))
4 bj-elid4 36704 . . 3 (𝐵 ∈ (𝐴 × V) → (𝐵 ∈ I ↔ (1st𝐵) = (2nd𝐵)))
54pm5.32i 573 . 2 ((𝐵 ∈ (𝐴 × V) ∧ 𝐵 ∈ I ) ↔ (𝐵 ∈ (𝐴 × V) ∧ (1st𝐵) = (2nd𝐵)))
6 1st2nd2 8030 . . . . 5 (𝐵 ∈ (𝐴 × V) → 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩)
76pm4.71ri 559 . . . 4 (𝐵 ∈ (𝐴 × V) ↔ (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × V)))
8 eleq1 2813 . . . . . . . 8 (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ → (𝐵 ∈ (𝐴 × V) ↔ ⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × V)))
98adantl 480 . . . . . . 7 (((1st𝐵) = (2nd𝐵) ∧ 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩) → (𝐵 ∈ (𝐴 × V) ↔ ⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × V)))
10 simpl 481 . . . . . . . . . . . 12 (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) → (1st𝐵) ∈ 𝐴)
1110a1i 11 . . . . . . . . . . 11 ((1st𝐵) = (2nd𝐵) → (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) → (1st𝐵) ∈ 𝐴))
12 eleq1 2813 . . . . . . . . . . . 12 ((1st𝐵) = (2nd𝐵) → ((1st𝐵) ∈ 𝐴 ↔ (2nd𝐵) ∈ 𝐴))
1310, 12imbitrid 243 . . . . . . . . . . 11 ((1st𝐵) = (2nd𝐵) → (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) → (2nd𝐵) ∈ 𝐴))
1411, 13jcad 511 . . . . . . . . . 10 ((1st𝐵) = (2nd𝐵) → (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) → ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ 𝐴)))
15 elex 3482 . . . . . . . . . . 11 ((2nd𝐵) ∈ 𝐴 → (2nd𝐵) ∈ V)
1615anim2i 615 . . . . . . . . . 10 (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ 𝐴) → ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V))
1714, 16impbid1 224 . . . . . . . . 9 ((1st𝐵) = (2nd𝐵) → (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) ↔ ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ 𝐴)))
1817adantr 479 . . . . . . . 8 (((1st𝐵) = (2nd𝐵) ∧ 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩) → (((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V) ↔ ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ 𝐴)))
19 opelxp 5708 . . . . . . . 8 (⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × V) ↔ ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ V))
20 opelxp 5708 . . . . . . . 8 (⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × 𝐴) ↔ ((1st𝐵) ∈ 𝐴 ∧ (2nd𝐵) ∈ 𝐴))
2118, 19, 203bitr4g 313 . . . . . . 7 (((1st𝐵) = (2nd𝐵) ∧ 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩) → (⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × V) ↔ ⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × 𝐴)))
22 eleq1 2813 . . . . . . . . 9 (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ → (𝐵 ∈ (𝐴 × 𝐴) ↔ ⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × 𝐴)))
2322bicomd 222 . . . . . . . 8 (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ → (⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × 𝐴) ↔ 𝐵 ∈ (𝐴 × 𝐴)))
2423adantl 480 . . . . . . 7 (((1st𝐵) = (2nd𝐵) ∧ 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩) → (⟨(1st𝐵), (2nd𝐵)⟩ ∈ (𝐴 × 𝐴) ↔ 𝐵 ∈ (𝐴 × 𝐴)))
259, 21, 243bitrd 304 . . . . . 6 (((1st𝐵) = (2nd𝐵) ∧ 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩) → (𝐵 ∈ (𝐴 × V) ↔ 𝐵 ∈ (𝐴 × 𝐴)))
2625pm5.32da 577 . . . . 5 ((1st𝐵) = (2nd𝐵) → ((𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × V)) ↔ (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × 𝐴))))
27 simpr 483 . . . . . 6 ((𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × 𝐴)) → 𝐵 ∈ (𝐴 × 𝐴))
28 1st2nd2 8030 . . . . . . 7 (𝐵 ∈ (𝐴 × 𝐴) → 𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩)
2928ancri 548 . . . . . 6 (𝐵 ∈ (𝐴 × 𝐴) → (𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × 𝐴)))
3027, 29impbii 208 . . . . 5 ((𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × 𝐴)) ↔ 𝐵 ∈ (𝐴 × 𝐴))
3126, 30bitrdi 286 . . . 4 ((1st𝐵) = (2nd𝐵) → ((𝐵 = ⟨(1st𝐵), (2nd𝐵)⟩ ∧ 𝐵 ∈ (𝐴 × V)) ↔ 𝐵 ∈ (𝐴 × 𝐴)))
327, 31bitrid 282 . . 3 ((1st𝐵) = (2nd𝐵) → (𝐵 ∈ (𝐴 × V) ↔ 𝐵 ∈ (𝐴 × 𝐴)))
3332pm5.32ri 574 . 2 ((𝐵 ∈ (𝐴 × V) ∧ (1st𝐵) = (2nd𝐵)) ↔ (𝐵 ∈ (𝐴 × 𝐴) ∧ (1st𝐵) = (2nd𝐵)))
343, 5, 333bitri 296 1 (𝐵 ∈ ( I ↾ 𝐴) ↔ (𝐵 ∈ (𝐴 × 𝐴) ∧ (1st𝐵) = (2nd𝐵)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 394   = wceq 1533  wcel 2098  Vcvv 3463  cop 4630   I cid 5569   × cxp 5670  cres 5674  cfv 6543  1st c1st 7989  2nd c2nd 7990
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2166  ax-ext 2696  ax-sep 5294  ax-nul 5301  ax-pr 5423  ax-un 7738
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2528  df-eu 2557  df-clab 2703  df-cleq 2717  df-clel 2802  df-nfc 2877  df-ne 2931  df-ral 3052  df-rex 3061  df-rab 3420  df-v 3465  df-dif 3942  df-un 3944  df-in 3946  df-ss 3956  df-nul 4319  df-if 4525  df-sn 4625  df-pr 4627  df-op 4631  df-uni 4904  df-br 5144  df-opab 5206  df-mpt 5227  df-id 5570  df-xp 5678  df-rel 5679  df-cnv 5680  df-co 5681  df-dm 5682  df-rn 5683  df-res 5684  df-iota 6495  df-fun 6545  df-fv 6551  df-1st 7991  df-2nd 7992
This theorem is referenced by: (None)
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