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Theorem ntrk2imkb 40271
 Description: If an interior function is contracting, the interiors of disjoint sets are disjoint. Kuratowski's K2 axiom implies KB. Interior version. (Contributed by RP, 9-Jun-2021.)
Assertion
Ref Expression
ntrk2imkb (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 → ∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅))
Distinct variable groups:   𝐵,𝑠,𝑡   𝐼,𝑠,𝑡

Proof of Theorem ntrk2imkb
StepHypRef Expression
1 id 22 . . 3 (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 → ∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠)
2 fveq2 6669 . . . . . 6 (𝑠 = 𝑡 → (𝐼𝑠) = (𝐼𝑡))
3 id 22 . . . . . 6 (𝑠 = 𝑡𝑠 = 𝑡)
42, 3sseq12d 4004 . . . . 5 (𝑠 = 𝑡 → ((𝐼𝑠) ⊆ 𝑠 ↔ (𝐼𝑡) ⊆ 𝑡))
54cbvralvw 3455 . . . 4 (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 ↔ ∀𝑡 ∈ 𝒫 𝐵(𝐼𝑡) ⊆ 𝑡)
65biimpi 217 . . 3 (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 → ∀𝑡 ∈ 𝒫 𝐵(𝐼𝑡) ⊆ 𝑡)
7 raaanv 4464 . . 3 (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) ↔ (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 ∧ ∀𝑡 ∈ 𝒫 𝐵(𝐼𝑡) ⊆ 𝑡))
81, 6, 7sylanbrc 583 . 2 (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 → ∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡))
9 ss2in 4217 . . . . . . 7 (((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) → ((𝐼𝑠) ∩ (𝐼𝑡)) ⊆ (𝑠𝑡))
109adantr 481 . . . . . 6 ((((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) ∧ (𝑠𝑡) = ∅) → ((𝐼𝑠) ∩ (𝐼𝑡)) ⊆ (𝑠𝑡))
11 simpr 485 . . . . . 6 ((((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) ∧ (𝑠𝑡) = ∅) → (𝑠𝑡) = ∅)
1210, 11sseqtrd 4011 . . . . 5 ((((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) ∧ (𝑠𝑡) = ∅) → ((𝐼𝑠) ∩ (𝐼𝑡)) ⊆ ∅)
13 ss0 4356 . . . . 5 (((𝐼𝑠) ∩ (𝐼𝑡)) ⊆ ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅)
1412, 13syl 17 . . . 4 ((((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) ∧ (𝑠𝑡) = ∅) → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅)
1514ex 413 . . 3 (((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) → ((𝑠𝑡) = ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅))
16152ralimi 3166 . 2 (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝐼𝑠) ⊆ 𝑠 ∧ (𝐼𝑡) ⊆ 𝑡) → ∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅))
178, 16syl 17 1 (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 → ∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ wa 396   = wceq 1530  ∀wral 3143   ∩ cin 3939   ⊆ wss 3940  ∅c0 4295  𝒫 cpw 4542  ‘cfv 6354 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 1904  ax-6 1963  ax-7 2008  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2153  ax-12 2169  ax-ext 2798 This theorem depends on definitions:  df-bi 208  df-an 397  df-or 844  df-3an 1083  df-tru 1533  df-ex 1774  df-nf 1778  df-sb 2063  df-clab 2805  df-cleq 2819  df-clel 2898  df-nfc 2968  df-ne 3022  df-ral 3148  df-rex 3149  df-rab 3152  df-v 3502  df-dif 3943  df-un 3945  df-in 3947  df-ss 3956  df-nul 4296  df-if 4471  df-sn 4565  df-pr 4567  df-op 4571  df-uni 4838  df-br 5064  df-iota 6313  df-fv 6362 This theorem is referenced by: (None)
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