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Theorem hausdiag 21675
 Description: A topology is Hausdorff iff the diagonal set is closed in the topology's product with itself. EDITORIAL: very clumsy proof, can probably be shortened substantially. (Contributed by Stefan O'Rear, 25-Jan-2015.)
Hypothesis
Ref Expression
hausdiag.x 𝑋 = 𝐽
Assertion
Ref Expression
hausdiag (𝐽 ∈ Haus ↔ (𝐽 ∈ Top ∧ ( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽))))

Proof of Theorem hausdiag
Dummy variables 𝑎 𝑏 𝑐 𝑑 𝑒 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 hausdiag.x . . 3 𝑋 = 𝐽
21ishaus 21353 . 2 (𝐽 ∈ Haus ↔ (𝐽 ∈ Top ∧ ∀𝑎𝑋𝑏𝑋 (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅))))
3 txtop 21599 . . . . . 6 ((𝐽 ∈ Top ∧ 𝐽 ∈ Top) → (𝐽 ×t 𝐽) ∈ Top)
43anidms 677 . . . . 5 (𝐽 ∈ Top → (𝐽 ×t 𝐽) ∈ Top)
5 f1oi 6314 . . . . . . 7 ( I ↾ 𝑋):𝑋1-1-onto𝑋
6 f1of 6277 . . . . . . 7 (( I ↾ 𝑋):𝑋1-1-onto𝑋 → ( I ↾ 𝑋):𝑋𝑋)
7 fssxp 6199 . . . . . . 7 (( I ↾ 𝑋):𝑋𝑋 → ( I ↾ 𝑋) ⊆ (𝑋 × 𝑋))
85, 6, 7mp2b 10 . . . . . 6 ( I ↾ 𝑋) ⊆ (𝑋 × 𝑋)
91, 1txuni 21622 . . . . . . 7 ((𝐽 ∈ Top ∧ 𝐽 ∈ Top) → (𝑋 × 𝑋) = (𝐽 ×t 𝐽))
109anidms 677 . . . . . 6 (𝐽 ∈ Top → (𝑋 × 𝑋) = (𝐽 ×t 𝐽))
118, 10syl5sseq 3799 . . . . 5 (𝐽 ∈ Top → ( I ↾ 𝑋) ⊆ (𝐽 ×t 𝐽))
12 eqid 2769 . . . . . 6 (𝐽 ×t 𝐽) = (𝐽 ×t 𝐽)
1312iscld2 21059 . . . . 5 (((𝐽 ×t 𝐽) ∈ Top ∧ ( I ↾ 𝑋) ⊆ (𝐽 ×t 𝐽)) → (( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽)) ↔ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ∈ (𝐽 ×t 𝐽)))
144, 11, 13syl2anc 693 . . . 4 (𝐽 ∈ Top → (( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽)) ↔ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ∈ (𝐽 ×t 𝐽)))
15 eltx 21598 . . . . 5 ((𝐽 ∈ Top ∧ 𝐽 ∈ Top) → (( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ∈ (𝐽 ×t 𝐽) ↔ ∀𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))
1615anidms 677 . . . 4 (𝐽 ∈ Top → (( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ∈ (𝐽 ×t 𝐽) ↔ ∀𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))
17 eldif 3730 . . . . . . . . . 10 (𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ↔ (𝑒 (𝐽 ×t 𝐽) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋)))
1810eqcomd 2775 . . . . . . . . . . . 12 (𝐽 ∈ Top → (𝐽 ×t 𝐽) = (𝑋 × 𝑋))
1918eleq2d 2834 . . . . . . . . . . 11 (𝐽 ∈ Top → (𝑒 (𝐽 ×t 𝐽) ↔ 𝑒 ∈ (𝑋 × 𝑋)))
2019anbi1d 740 . . . . . . . . . 10 (𝐽 ∈ Top → ((𝑒 (𝐽 ×t 𝐽) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋)) ↔ (𝑒 ∈ (𝑋 × 𝑋) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋))))
2117, 20syl5bb 272 . . . . . . . . 9 (𝐽 ∈ Top → (𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ↔ (𝑒 ∈ (𝑋 × 𝑋) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋))))
2221imbi1d 330 . . . . . . . 8 (𝐽 ∈ Top → ((𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ ((𝑒 ∈ (𝑋 × 𝑋) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋)) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))))
23 impexp 462 . . . . . . . 8 (((𝑒 ∈ (𝑋 × 𝑋) ∧ ¬ 𝑒 ∈ ( I ↾ 𝑋)) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ (𝑒 ∈ (𝑋 × 𝑋) → (¬ 𝑒 ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))))
2422, 23syl6bb 276 . . . . . . 7 (𝐽 ∈ Top → ((𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ (𝑒 ∈ (𝑋 × 𝑋) → (¬ 𝑒 ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))))
2524ralbidv2 3131 . . . . . 6 (𝐽 ∈ Top → (∀𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ∀𝑒 ∈ (𝑋 × 𝑋)(¬ 𝑒 ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))))
26 eleq1 2836 . . . . . . . . 9 (𝑒 = ⟨𝑎, 𝑏⟩ → (𝑒 ∈ ( I ↾ 𝑋) ↔ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋)))
2726notbid 307 . . . . . . . 8 (𝑒 = ⟨𝑎, 𝑏⟩ → (¬ 𝑒 ∈ ( I ↾ 𝑋) ↔ ¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋)))
28 eleq1 2836 . . . . . . . . . 10 (𝑒 = ⟨𝑎, 𝑏⟩ → (𝑒 ∈ (𝑐 × 𝑑) ↔ ⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑)))
2928anbi1d 740 . . . . . . . . 9 (𝑒 = ⟨𝑎, 𝑏⟩ → ((𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))
30292rexbidv 3203 . . . . . . . 8 (𝑒 = ⟨𝑎, 𝑏⟩ → (∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))
3127, 30imbi12d 333 . . . . . . 7 (𝑒 = ⟨𝑎, 𝑏⟩ → ((¬ 𝑒 ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ (¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))))
3231ralxp 5401 . . . . . 6 (∀𝑒 ∈ (𝑋 × 𝑋)(¬ 𝑒 ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ ∀𝑎𝑋𝑏𝑋 (¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))))
3325, 32syl6bb 276 . . . . 5 (𝐽 ∈ Top → (∀𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ∀𝑎𝑋𝑏𝑋 (¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))))
34 vex 3351 . . . . . . . . . . 11 𝑏 ∈ V
3534opelres 5541 . . . . . . . . . 10 (⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) ↔ (⟨𝑎, 𝑏⟩ ∈ I ∧ 𝑎𝑋))
36 df-br 4784 . . . . . . . . . . . 12 (𝑎 I 𝑏 ↔ ⟨𝑎, 𝑏⟩ ∈ I )
3734ideq 5412 . . . . . . . . . . . 12 (𝑎 I 𝑏𝑎 = 𝑏)
3836, 37bitr3i 266 . . . . . . . . . . 11 (⟨𝑎, 𝑏⟩ ∈ I ↔ 𝑎 = 𝑏)
39 iba 526 . . . . . . . . . . . 12 (𝑎𝑋 → (⟨𝑎, 𝑏⟩ ∈ I ↔ (⟨𝑎, 𝑏⟩ ∈ I ∧ 𝑎𝑋)))
4039adantr 473 . . . . . . . . . . 11 ((𝑎𝑋𝑏𝑋) → (⟨𝑎, 𝑏⟩ ∈ I ↔ (⟨𝑎, 𝑏⟩ ∈ I ∧ 𝑎𝑋)))
4138, 40syl5rbbr 275 . . . . . . . . . 10 ((𝑎𝑋𝑏𝑋) → ((⟨𝑎, 𝑏⟩ ∈ I ∧ 𝑎𝑋) ↔ 𝑎 = 𝑏))
4235, 41syl5bb 272 . . . . . . . . 9 ((𝑎𝑋𝑏𝑋) → (⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) ↔ 𝑎 = 𝑏))
4342adantl 474 . . . . . . . 8 ((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) → (⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) ↔ 𝑎 = 𝑏))
4443necon3bbid 2978 . . . . . . 7 ((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) → (¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) ↔ 𝑎𝑏))
45 elssuni 4600 . . . . . . . . . . . . . . . 16 (𝑐𝐽𝑐 𝐽)
46 elssuni 4600 . . . . . . . . . . . . . . . 16 (𝑑𝐽𝑑 𝐽)
47 xpss12 5263 . . . . . . . . . . . . . . . 16 ((𝑐 𝐽𝑑 𝐽) → (𝑐 × 𝑑) ⊆ ( 𝐽 × 𝐽))
4845, 46, 47syl2an 496 . . . . . . . . . . . . . . 15 ((𝑐𝐽𝑑𝐽) → (𝑐 × 𝑑) ⊆ ( 𝐽 × 𝐽))
491, 1xpeq12i 5276 . . . . . . . . . . . . . . 15 (𝑋 × 𝑋) = ( 𝐽 × 𝐽)
5048, 49syl6sseqr 3798 . . . . . . . . . . . . . 14 ((𝑐𝐽𝑑𝐽) → (𝑐 × 𝑑) ⊆ (𝑋 × 𝑋))
5150adantl 474 . . . . . . . . . . . . 13 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (𝑐 × 𝑑) ⊆ (𝑋 × 𝑋))
5210ad2antrr 761 . . . . . . . . . . . . 13 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (𝑋 × 𝑋) = (𝐽 ×t 𝐽))
5351, 52sseqtrd 3787 . . . . . . . . . . . 12 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (𝑐 × 𝑑) ⊆ (𝐽 ×t 𝐽))
54 reldisj 4160 . . . . . . . . . . . 12 ((𝑐 × 𝑑) ⊆ (𝐽 ×t 𝐽) → (((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ∅ ↔ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))
5553, 54syl 17 . . . . . . . . . . 11 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ∅ ↔ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))
56 df-res 5260 . . . . . . . . . . . . . . 15 ( I ↾ 𝑋) = ( I ∩ (𝑋 × V))
5756ineq2i 3959 . . . . . . . . . . . . . 14 ((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ((𝑐 × 𝑑) ∩ ( I ∩ (𝑋 × V)))
58 inass 3969 . . . . . . . . . . . . . . 15 (((𝑐 × 𝑑) ∩ I ) ∩ (𝑋 × V)) = ((𝑐 × 𝑑) ∩ ( I ∩ (𝑋 × V)))
59 inss1 3978 . . . . . . . . . . . . . . . . . 18 ((𝑐 × 𝑑) ∩ I ) ⊆ (𝑐 × 𝑑)
6059, 51syl5ss 3760 . . . . . . . . . . . . . . . . 17 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((𝑐 × 𝑑) ∩ I ) ⊆ (𝑋 × 𝑋))
61 ssv 3771 . . . . . . . . . . . . . . . . . 18 𝑋 ⊆ V
62 xpss2 5267 . . . . . . . . . . . . . . . . . 18 (𝑋 ⊆ V → (𝑋 × 𝑋) ⊆ (𝑋 × V))
6361, 62ax-mp 5 . . . . . . . . . . . . . . . . 17 (𝑋 × 𝑋) ⊆ (𝑋 × V)
6460, 63syl6ss 3761 . . . . . . . . . . . . . . . 16 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((𝑐 × 𝑑) ∩ I ) ⊆ (𝑋 × V))
65 df-ss 3734 . . . . . . . . . . . . . . . 16 (((𝑐 × 𝑑) ∩ I ) ⊆ (𝑋 × V) ↔ (((𝑐 × 𝑑) ∩ I ) ∩ (𝑋 × V)) = ((𝑐 × 𝑑) ∩ I ))
6664, 65sylib 208 . . . . . . . . . . . . . . 15 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (((𝑐 × 𝑑) ∩ I ) ∩ (𝑋 × V)) = ((𝑐 × 𝑑) ∩ I ))
6758, 66syl5eqr 2817 . . . . . . . . . . . . . 14 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((𝑐 × 𝑑) ∩ ( I ∩ (𝑋 × V))) = ((𝑐 × 𝑑) ∩ I ))
6857, 67syl5eq 2815 . . . . . . . . . . . . 13 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ((𝑐 × 𝑑) ∩ I ))
6968eqeq1d 2771 . . . . . . . . . . . 12 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ∅ ↔ ((𝑐 × 𝑑) ∩ I ) = ∅))
70 opelxp 5285 . . . . . . . . . . . . . . . 16 (⟨𝑎, 𝑎⟩ ∈ (𝑐 × 𝑑) ↔ (𝑎𝑐𝑎𝑑))
71 df-br 4784 . . . . . . . . . . . . . . . 16 (𝑎(𝑐 × 𝑑)𝑎 ↔ ⟨𝑎, 𝑎⟩ ∈ (𝑐 × 𝑑))
72 elin 3944 . . . . . . . . . . . . . . . 16 (𝑎 ∈ (𝑐𝑑) ↔ (𝑎𝑐𝑎𝑑))
7370, 71, 723bitr4i 292 . . . . . . . . . . . . . . 15 (𝑎(𝑐 × 𝑑)𝑎𝑎 ∈ (𝑐𝑑))
7473notbii 309 . . . . . . . . . . . . . 14 𝑎(𝑐 × 𝑑)𝑎 ↔ ¬ 𝑎 ∈ (𝑐𝑑))
7574albii 1893 . . . . . . . . . . . . 13 (∀𝑎 ¬ 𝑎(𝑐 × 𝑑)𝑎 ↔ ∀𝑎 ¬ 𝑎 ∈ (𝑐𝑑))
76 intirr 5654 . . . . . . . . . . . . 13 (((𝑐 × 𝑑) ∩ I ) = ∅ ↔ ∀𝑎 ¬ 𝑎(𝑐 × 𝑑)𝑎)
77 eq0 4073 . . . . . . . . . . . . 13 ((𝑐𝑑) = ∅ ↔ ∀𝑎 ¬ 𝑎 ∈ (𝑐𝑑))
7875, 76, 773bitr4i 292 . . . . . . . . . . . 12 (((𝑐 × 𝑑) ∩ I ) = ∅ ↔ (𝑐𝑑) = ∅)
7969, 78syl6bb 276 . . . . . . . . . . 11 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (((𝑐 × 𝑑) ∩ ( I ↾ 𝑋)) = ∅ ↔ (𝑐𝑑) = ∅))
8055, 79bitr3d 270 . . . . . . . . . 10 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)) ↔ (𝑐𝑑) = ∅))
8180anbi2d 739 . . . . . . . . 9 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → (((𝑎𝑐𝑏𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ((𝑎𝑐𝑏𝑑) ∧ (𝑐𝑑) = ∅)))
82 opelxp 5285 . . . . . . . . . 10 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ↔ (𝑎𝑐𝑏𝑑))
8382anbi1i 730 . . . . . . . . 9 ((⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ((𝑎𝑐𝑏𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))))
84 df-3an 1071 . . . . . . . . 9 ((𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅) ↔ ((𝑎𝑐𝑏𝑑) ∧ (𝑐𝑑) = ∅))
8581, 83, 843bitr4g 303 . . . . . . . 8 (((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) ∧ (𝑐𝐽𝑑𝐽)) → ((⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅)))
86852rexbidva 3202 . . . . . . 7 ((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) → (∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅)))
8744, 86imbi12d 333 . . . . . 6 ((𝐽 ∈ Top ∧ (𝑎𝑋𝑏𝑋)) → ((¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅))))
88872ralbidva 3135 . . . . 5 (𝐽 ∈ Top → (∀𝑎𝑋𝑏𝑋 (¬ ⟨𝑎, 𝑏⟩ ∈ ( I ↾ 𝑋) → ∃𝑐𝐽𝑑𝐽 (⟨𝑎, 𝑏⟩ ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋)))) ↔ ∀𝑎𝑋𝑏𝑋 (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅))))
8933, 88bitrd 268 . . . 4 (𝐽 ∈ Top → (∀𝑒 ∈ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))∃𝑐𝐽𝑑𝐽 (𝑒 ∈ (𝑐 × 𝑑) ∧ (𝑐 × 𝑑) ⊆ ( (𝐽 ×t 𝐽) ∖ ( I ↾ 𝑋))) ↔ ∀𝑎𝑋𝑏𝑋 (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅))))
9014, 16, 893bitrrd 295 . . 3 (𝐽 ∈ Top → (∀𝑎𝑋𝑏𝑋 (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅)) ↔ ( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽))))
9190pm5.32i 669 . 2 ((𝐽 ∈ Top ∧ ∀𝑎𝑋𝑏𝑋 (𝑎𝑏 → ∃𝑐𝐽𝑑𝐽 (𝑎𝑐𝑏𝑑 ∧ (𝑐𝑑) = ∅))) ↔ (𝐽 ∈ Top ∧ ( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽))))
922, 91bitri 264 1 (𝐽 ∈ Haus ↔ (𝐽 ∈ Top ∧ ( I ↾ 𝑋) ∈ (Clsd‘(𝐽 ×t 𝐽))))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 196   ∧ wa 383   ∧ w3a 1069  ∀wal 1627   = wceq 1629   ∈ wcel 2143   ≠ wne 2941  ∀wral 3059  ∃wrex 3060  Vcvv 3348   ∖ cdif 3717   ∩ cin 3719   ⊆ wss 3720  ∅c0 4060  ⟨cop 4319  ∪ cuni 4571   class class class wbr 4783   I cid 5155   × cxp 5246   ↾ cres 5250  ⟶wf 6026  –1-1-onto→wf1o 6029  ‘cfv 6030  (class class class)co 6791  Topctop 20924  Clsdccld 21047  Hauscha 21339   ×t ctx 21590 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1868  ax-4 1883  ax-5 1989  ax-6 2055  ax-7 2091  ax-8 2145  ax-9 2152  ax-10 2172  ax-11 2188  ax-12 2201  ax-13 2406  ax-ext 2749  ax-sep 4911  ax-nul 4919  ax-pow 4970  ax-pr 5033  ax-un 7094 This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3an 1071  df-tru 1632  df-ex 1851  df-nf 1856  df-sb 2048  df-eu 2620  df-mo 2621  df-clab 2756  df-cleq 2762  df-clel 2765  df-nfc 2900  df-ne 2942  df-ral 3064  df-rex 3065  df-rab 3068  df-v 3350  df-sbc 3585  df-csb 3680  df-dif 3723  df-un 3725  df-in 3727  df-ss 3734  df-nul 4061  df-if 4223  df-pw 4296  df-sn 4314  df-pr 4316  df-op 4320  df-uni 4572  df-iun 4653  df-br 4784  df-opab 4844  df-mpt 4861  df-id 5156  df-xp 5254  df-rel 5255  df-cnv 5256  df-co 5257  df-dm 5258  df-rn 5259  df-res 5260  df-ima 5261  df-iota 5993  df-fun 6032  df-fn 6033  df-f 6034  df-f1 6035  df-fo 6036  df-f1o 6037  df-fv 6038  df-ov 6794  df-oprab 6795  df-mpt2 6796  df-1st 7313  df-2nd 7314  df-topgen 16318  df-top 20925  df-topon 20942  df-bases 20977  df-cld 21050  df-haus 21346  df-tx 21592 This theorem is referenced by:  hauseqlcld  21676  tgphaus  22146  qtophaus  30244
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