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Theorem txbas 12441
 Description: The set of Cartesian products of elements from two topological bases is a basis. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 31-Aug-2015.)
Hypothesis
Ref Expression
txval.1 𝐵 = ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))
Assertion
Ref Expression
txbas ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → 𝐵 ∈ TopBases)
Distinct variable groups:   𝑥,𝑦,𝑅   𝑥,𝑆,𝑦
Allowed substitution hints:   𝐵(𝑥,𝑦)

Proof of Theorem txbas
Dummy variables 𝑎 𝑏 𝑐 𝑑 𝑝 𝑡 𝑢 𝑣 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 txval.1 . . . . . . . 8 𝐵 = ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))
2 xpeq1 4553 . . . . . . . . . 10 (𝑥 = 𝑎 → (𝑥 × 𝑦) = (𝑎 × 𝑦))
3 xpeq2 4554 . . . . . . . . . 10 (𝑦 = 𝑏 → (𝑎 × 𝑦) = (𝑎 × 𝑏))
42, 3cbvmpov 5851 . . . . . . . . 9 (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦)) = (𝑎𝑅, 𝑏𝑆 ↦ (𝑎 × 𝑏))
54rnmpo 5881 . . . . . . . 8 ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦)) = {𝑢 ∣ ∃𝑎𝑅𝑏𝑆 𝑢 = (𝑎 × 𝑏)}
61, 5eqtri 2160 . . . . . . 7 𝐵 = {𝑢 ∣ ∃𝑎𝑅𝑏𝑆 𝑢 = (𝑎 × 𝑏)}
76abeq2i 2250 . . . . . 6 (𝑢𝐵 ↔ ∃𝑎𝑅𝑏𝑆 𝑢 = (𝑎 × 𝑏))
8 xpeq1 4553 . . . . . . . . . 10 (𝑥 = 𝑐 → (𝑥 × 𝑦) = (𝑐 × 𝑦))
9 xpeq2 4554 . . . . . . . . . 10 (𝑦 = 𝑑 → (𝑐 × 𝑦) = (𝑐 × 𝑑))
108, 9cbvmpov 5851 . . . . . . . . 9 (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦)) = (𝑐𝑅, 𝑑𝑆 ↦ (𝑐 × 𝑑))
1110rnmpo 5881 . . . . . . . 8 ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦)) = {𝑣 ∣ ∃𝑐𝑅𝑑𝑆 𝑣 = (𝑐 × 𝑑)}
121, 11eqtri 2160 . . . . . . 7 𝐵 = {𝑣 ∣ ∃𝑐𝑅𝑑𝑆 𝑣 = (𝑐 × 𝑑)}
1312abeq2i 2250 . . . . . 6 (𝑣𝐵 ↔ ∃𝑐𝑅𝑑𝑆 𝑣 = (𝑐 × 𝑑))
147, 13anbi12i 455 . . . . 5 ((𝑢𝐵𝑣𝐵) ↔ (∃𝑎𝑅𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑐𝑅𝑑𝑆 𝑣 = (𝑐 × 𝑑)))
15 reeanv 2600 . . . . 5 (∃𝑎𝑅𝑐𝑅 (∃𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑑𝑆 𝑣 = (𝑐 × 𝑑)) ↔ (∃𝑎𝑅𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑐𝑅𝑑𝑆 𝑣 = (𝑐 × 𝑑)))
1614, 15bitr4i 186 . . . 4 ((𝑢𝐵𝑣𝐵) ↔ ∃𝑎𝑅𝑐𝑅 (∃𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑑𝑆 𝑣 = (𝑐 × 𝑑)))
17 reeanv 2600 . . . . . 6 (∃𝑏𝑆𝑑𝑆 (𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) ↔ (∃𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑑𝑆 𝑣 = (𝑐 × 𝑑)))
18 basis2 12229 . . . . . . . . . . . . . . . 16 (((𝑅 ∈ TopBases ∧ 𝑎𝑅) ∧ (𝑐𝑅𝑢 ∈ (𝑎𝑐))) → ∃𝑥𝑅 (𝑢𝑥𝑥 ⊆ (𝑎𝑐)))
1918exp43 369 . . . . . . . . . . . . . . 15 (𝑅 ∈ TopBases → (𝑎𝑅 → (𝑐𝑅 → (𝑢 ∈ (𝑎𝑐) → ∃𝑥𝑅 (𝑢𝑥𝑥 ⊆ (𝑎𝑐))))))
2019imp42 351 . . . . . . . . . . . . . 14 (((𝑅 ∈ TopBases ∧ (𝑎𝑅𝑐𝑅)) ∧ 𝑢 ∈ (𝑎𝑐)) → ∃𝑥𝑅 (𝑢𝑥𝑥 ⊆ (𝑎𝑐)))
21 basis2 12229 . . . . . . . . . . . . . . . 16 (((𝑆 ∈ TopBases ∧ 𝑏𝑆) ∧ (𝑑𝑆𝑣 ∈ (𝑏𝑑))) → ∃𝑦𝑆 (𝑣𝑦𝑦 ⊆ (𝑏𝑑)))
2221exp43 369 . . . . . . . . . . . . . . 15 (𝑆 ∈ TopBases → (𝑏𝑆 → (𝑑𝑆 → (𝑣 ∈ (𝑏𝑑) → ∃𝑦𝑆 (𝑣𝑦𝑦 ⊆ (𝑏𝑑))))))
2322imp42 351 . . . . . . . . . . . . . 14 (((𝑆 ∈ TopBases ∧ (𝑏𝑆𝑑𝑆)) ∧ 𝑣 ∈ (𝑏𝑑)) → ∃𝑦𝑆 (𝑣𝑦𝑦 ⊆ (𝑏𝑑)))
24 reeanv 2600 . . . . . . . . . . . . . . 15 (∃𝑥𝑅𝑦𝑆 ((𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ (𝑣𝑦𝑦 ⊆ (𝑏𝑑))) ↔ (∃𝑥𝑅 (𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ ∃𝑦𝑆 (𝑣𝑦𝑦 ⊆ (𝑏𝑑))))
25 opelxpi 4571 . . . . . . . . . . . . . . . . . . 19 ((𝑢𝑥𝑣𝑦) → ⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦))
26 xpss12 4646 . . . . . . . . . . . . . . . . . . 19 ((𝑥 ⊆ (𝑎𝑐) ∧ 𝑦 ⊆ (𝑏𝑑)) → (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))
2725, 26anim12i 336 . . . . . . . . . . . . . . . . . 18 (((𝑢𝑥𝑣𝑦) ∧ (𝑥 ⊆ (𝑎𝑐) ∧ 𝑦 ⊆ (𝑏𝑑))) → (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
2827an4s 577 . . . . . . . . . . . . . . . . 17 (((𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ (𝑣𝑦𝑦 ⊆ (𝑏𝑑))) → (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
2928reximi 2529 . . . . . . . . . . . . . . . 16 (∃𝑦𝑆 ((𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ (𝑣𝑦𝑦 ⊆ (𝑏𝑑))) → ∃𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3029reximi 2529 . . . . . . . . . . . . . . 15 (∃𝑥𝑅𝑦𝑆 ((𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ (𝑣𝑦𝑦 ⊆ (𝑏𝑑))) → ∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3124, 30sylbir 134 . . . . . . . . . . . . . 14 ((∃𝑥𝑅 (𝑢𝑥𝑥 ⊆ (𝑎𝑐)) ∧ ∃𝑦𝑆 (𝑣𝑦𝑦 ⊆ (𝑏𝑑))) → ∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3220, 23, 31syl2an 287 . . . . . . . . . . . . 13 ((((𝑅 ∈ TopBases ∧ (𝑎𝑅𝑐𝑅)) ∧ 𝑢 ∈ (𝑎𝑐)) ∧ ((𝑆 ∈ TopBases ∧ (𝑏𝑆𝑑𝑆)) ∧ 𝑣 ∈ (𝑏𝑑))) → ∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3332an4s 577 . . . . . . . . . . . 12 ((((𝑅 ∈ TopBases ∧ (𝑎𝑅𝑐𝑅)) ∧ (𝑆 ∈ TopBases ∧ (𝑏𝑆𝑑𝑆))) ∧ (𝑢 ∈ (𝑎𝑐) ∧ 𝑣 ∈ (𝑏𝑑))) → ∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3433ralrimivva 2514 . . . . . . . . . . 11 (((𝑅 ∈ TopBases ∧ (𝑎𝑅𝑐𝑅)) ∧ (𝑆 ∈ TopBases ∧ (𝑏𝑆𝑑𝑆))) → ∀𝑢 ∈ (𝑎𝑐)∀𝑣 ∈ (𝑏𝑑)∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
35 eleq1 2202 . . . . . . . . . . . . . 14 (𝑝 = ⟨𝑢, 𝑣⟩ → (𝑝 ∈ (𝑥 × 𝑦) ↔ ⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦)))
3635anbi1d 460 . . . . . . . . . . . . 13 (𝑝 = ⟨𝑢, 𝑣⟩ → ((𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
37362rexbidv 2460 . . . . . . . . . . . 12 (𝑝 = ⟨𝑢, 𝑣⟩ → (∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
3837ralxp 4682 . . . . . . . . . . 11 (∀𝑝 ∈ ((𝑎𝑐) × (𝑏𝑑))∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∀𝑢 ∈ (𝑎𝑐)∀𝑣 ∈ (𝑏𝑑)∃𝑥𝑅𝑦𝑆 (⟨𝑢, 𝑣⟩ ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
3934, 38sylibr 133 . . . . . . . . . 10 (((𝑅 ∈ TopBases ∧ (𝑎𝑅𝑐𝑅)) ∧ (𝑆 ∈ TopBases ∧ (𝑏𝑆𝑑𝑆))) → ∀𝑝 ∈ ((𝑎𝑐) × (𝑏𝑑))∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
4039an4s 577 . . . . . . . . 9 (((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) ∧ ((𝑎𝑅𝑐𝑅) ∧ (𝑏𝑆𝑑𝑆))) → ∀𝑝 ∈ ((𝑎𝑐) × (𝑏𝑑))∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
4140anassrs 397 . . . . . . . 8 ((((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) ∧ (𝑎𝑅𝑐𝑅)) ∧ (𝑏𝑆𝑑𝑆)) → ∀𝑝 ∈ ((𝑎𝑐) × (𝑏𝑑))∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
42 ineq12 3272 . . . . . . . . . 10 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (𝑢𝑣) = ((𝑎 × 𝑏) ∩ (𝑐 × 𝑑)))
43 inxp 4673 . . . . . . . . . 10 ((𝑎 × 𝑏) ∩ (𝑐 × 𝑑)) = ((𝑎𝑐) × (𝑏𝑑))
4442, 43syl6eq 2188 . . . . . . . . 9 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (𝑢𝑣) = ((𝑎𝑐) × (𝑏𝑑)))
4544sseq2d 3127 . . . . . . . . . . . 12 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (𝑡 ⊆ (𝑢𝑣) ↔ 𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))))
4645anbi2d 459 . . . . . . . . . . 11 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → ((𝑝𝑡𝑡 ⊆ (𝑢𝑣)) ↔ (𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
4746rexbidv 2438 . . . . . . . . . 10 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣)) ↔ ∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
481rexeqi 2631 . . . . . . . . . . 11 (∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑡 ∈ ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))(𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))))
49 1stexg 6065 . . . . . . . . . . . . . . 15 (𝑧 ∈ V → (1st𝑧) ∈ V)
5049elv 2690 . . . . . . . . . . . . . 14 (1st𝑧) ∈ V
51 2ndexg 6066 . . . . . . . . . . . . . . 15 (𝑧 ∈ V → (2nd𝑧) ∈ V)
5251elv 2690 . . . . . . . . . . . . . 14 (2nd𝑧) ∈ V
5350, 52xpex 4654 . . . . . . . . . . . . 13 ((1st𝑧) × (2nd𝑧)) ∈ V
5453rgenw 2487 . . . . . . . . . . . 12 𝑧 ∈ (𝑅 × 𝑆)((1st𝑧) × (2nd𝑧)) ∈ V
55 vex 2689 . . . . . . . . . . . . . . . . 17 𝑥 ∈ V
56 vex 2689 . . . . . . . . . . . . . . . . 17 𝑦 ∈ V
5755, 56op1std 6046 . . . . . . . . . . . . . . . 16 (𝑧 = ⟨𝑥, 𝑦⟩ → (1st𝑧) = 𝑥)
5855, 56op2ndd 6047 . . . . . . . . . . . . . . . 16 (𝑧 = ⟨𝑥, 𝑦⟩ → (2nd𝑧) = 𝑦)
5957, 58xpeq12d 4564 . . . . . . . . . . . . . . 15 (𝑧 = ⟨𝑥, 𝑦⟩ → ((1st𝑧) × (2nd𝑧)) = (𝑥 × 𝑦))
6059mpompt 5863 . . . . . . . . . . . . . 14 (𝑧 ∈ (𝑅 × 𝑆) ↦ ((1st𝑧) × (2nd𝑧))) = (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))
6160eqcomi 2143 . . . . . . . . . . . . 13 (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦)) = (𝑧 ∈ (𝑅 × 𝑆) ↦ ((1st𝑧) × (2nd𝑧)))
62 eleq2 2203 . . . . . . . . . . . . . 14 (𝑡 = ((1st𝑧) × (2nd𝑧)) → (𝑝𝑡𝑝 ∈ ((1st𝑧) × (2nd𝑧))))
63 sseq1 3120 . . . . . . . . . . . . . 14 (𝑡 = ((1st𝑧) × (2nd𝑧)) → (𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑)) ↔ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
6462, 63anbi12d 464 . . . . . . . . . . . . 13 (𝑡 = ((1st𝑧) × (2nd𝑧)) → ((𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ (𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ∧ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
6561, 64rexrnmpt 5563 . . . . . . . . . . . 12 (∀𝑧 ∈ (𝑅 × 𝑆)((1st𝑧) × (2nd𝑧)) ∈ V → (∃𝑡 ∈ ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))(𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑧 ∈ (𝑅 × 𝑆)(𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ∧ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
6654, 65ax-mp 5 . . . . . . . . . . 11 (∃𝑡 ∈ ran (𝑥𝑅, 𝑦𝑆 ↦ (𝑥 × 𝑦))(𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑧 ∈ (𝑅 × 𝑆)(𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ∧ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
6759eleq2d 2209 . . . . . . . . . . . . 13 (𝑧 = ⟨𝑥, 𝑦⟩ → (𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ↔ 𝑝 ∈ (𝑥 × 𝑦)))
6859sseq1d 3126 . . . . . . . . . . . . 13 (𝑧 = ⟨𝑥, 𝑦⟩ → (((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑)) ↔ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
6967, 68anbi12d 464 . . . . . . . . . . . 12 (𝑧 = ⟨𝑥, 𝑦⟩ → ((𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ∧ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
7069rexxp 4683 . . . . . . . . . . 11 (∃𝑧 ∈ (𝑅 × 𝑆)(𝑝 ∈ ((1st𝑧) × (2nd𝑧)) ∧ ((1st𝑧) × (2nd𝑧)) ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
7148, 66, 703bitri 205 . . . . . . . . . 10 (∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ ((𝑎𝑐) × (𝑏𝑑))) ↔ ∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑))))
7247, 71syl6bb 195 . . . . . . . . 9 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣)) ↔ ∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
7344, 72raleqbidv 2638 . . . . . . . 8 ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → (∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣)) ↔ ∀𝑝 ∈ ((𝑎𝑐) × (𝑏𝑑))∃𝑥𝑅𝑦𝑆 (𝑝 ∈ (𝑥 × 𝑦) ∧ (𝑥 × 𝑦) ⊆ ((𝑎𝑐) × (𝑏𝑑)))))
7441, 73syl5ibrcom 156 . . . . . . 7 ((((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) ∧ (𝑎𝑅𝑐𝑅)) ∧ (𝑏𝑆𝑑𝑆)) → ((𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → ∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
7574rexlimdvva 2557 . . . . . 6 (((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) ∧ (𝑎𝑅𝑐𝑅)) → (∃𝑏𝑆𝑑𝑆 (𝑢 = (𝑎 × 𝑏) ∧ 𝑣 = (𝑐 × 𝑑)) → ∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
7617, 75syl5bir 152 . . . . 5 (((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) ∧ (𝑎𝑅𝑐𝑅)) → ((∃𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑑𝑆 𝑣 = (𝑐 × 𝑑)) → ∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
7776rexlimdvva 2557 . . . 4 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → (∃𝑎𝑅𝑐𝑅 (∃𝑏𝑆 𝑢 = (𝑎 × 𝑏) ∧ ∃𝑑𝑆 𝑣 = (𝑐 × 𝑑)) → ∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
7816, 77syl5bi 151 . . 3 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → ((𝑢𝐵𝑣𝐵) → ∀𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
7978ralrimivv 2513 . 2 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → ∀𝑢𝐵𝑣𝐵𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣)))
801txbasex 12440 . . 3 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → 𝐵 ∈ V)
81 isbasis2g 12226 . . 3 (𝐵 ∈ V → (𝐵 ∈ TopBases ↔ ∀𝑢𝐵𝑣𝐵𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
8280, 81syl 14 . 2 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → (𝐵 ∈ TopBases ↔ ∀𝑢𝐵𝑣𝐵𝑝 ∈ (𝑢𝑣)∃𝑡𝐵 (𝑝𝑡𝑡 ⊆ (𝑢𝑣))))
8379, 82mpbird 166 1 ((𝑅 ∈ TopBases ∧ 𝑆 ∈ TopBases) → 𝐵 ∈ TopBases)
 Colors of variables: wff set class Syntax hints:   → wi 4   ∧ wa 103   ↔ wb 104   = wceq 1331   ∈ wcel 1480  {cab 2125  ∀wral 2416  ∃wrex 2417  Vcvv 2686   ∩ cin 3070   ⊆ wss 3071  ⟨cop 3530   ↦ cmpt 3989   × cxp 4537  ran crn 4540  ‘cfv 5123   ∈ cmpo 5776  1st c1st 6036  2nd c2nd 6037  TopBasesctb 12223 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 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-13 1491  ax-14 1492  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2121  ax-sep 4046  ax-pow 4098  ax-pr 4131  ax-un 4355 This theorem depends on definitions:  df-bi 116  df-3an 964  df-tru 1334  df-nf 1437  df-sb 1736  df-eu 2002  df-mo 2003  df-clab 2126  df-cleq 2132  df-clel 2135  df-nfc 2270  df-ral 2421  df-rex 2422  df-rab 2425  df-v 2688  df-sbc 2910  df-csb 3004  df-un 3075  df-in 3077  df-ss 3084  df-pw 3512  df-sn 3533  df-pr 3534  df-op 3536  df-uni 3737  df-iun 3815  df-br 3930  df-opab 3990  df-mpt 3991  df-id 4215  df-xp 4545  df-rel 4546  df-cnv 4547  df-co 4548  df-dm 4549  df-rn 4550  df-res 4551  df-ima 4552  df-iota 5088  df-fun 5125  df-fn 5126  df-f 5127  df-fo 5129  df-fv 5131  df-oprab 5778  df-mpo 5779  df-1st 6038  df-2nd 6039  df-bases 12224 This theorem is referenced by:  txtop  12443
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