Metamath Proof Explorer


Theorem txpconn

Description: The topological product of two path-connected spaces is path-connected. (Contributed by Mario Carneiro, 12-Feb-2015)

Ref Expression
Assertion txpconn ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( 𝑅 ×t 𝑆 ) ∈ PConn )

Proof

Step Hyp Ref Expression
1 pconntop ( 𝑅 ∈ PConn → 𝑅 ∈ Top )
2 pconntop ( 𝑆 ∈ PConn → 𝑆 ∈ Top )
3 txtop ( ( 𝑅 ∈ Top ∧ 𝑆 ∈ Top ) → ( 𝑅 ×t 𝑆 ) ∈ Top )
4 1 2 3 syl2an ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( 𝑅 ×t 𝑆 ) ∈ Top )
5 an6 ( ( ( 𝑅 ∈ PConn ∧ 𝑥 𝑅𝑧 𝑅 ) ∧ ( 𝑆 ∈ PConn ∧ 𝑦 𝑆𝑤 𝑆 ) ) ↔ ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) )
6 eqid 𝑅 = 𝑅
7 6 pconncn ( ( 𝑅 ∈ PConn ∧ 𝑥 𝑅𝑧 𝑅 ) → ∃ 𝑔 ∈ ( II Cn 𝑅 ) ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) )
8 eqid 𝑆 = 𝑆
9 8 pconncn ( ( 𝑆 ∈ PConn ∧ 𝑦 𝑆𝑤 𝑆 ) → ∃ ∈ ( II Cn 𝑆 ) ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) )
10 7 9 anim12i ( ( ( 𝑅 ∈ PConn ∧ 𝑥 𝑅𝑧 𝑅 ) ∧ ( 𝑆 ∈ PConn ∧ 𝑦 𝑆𝑤 𝑆 ) ) → ( ∃ 𝑔 ∈ ( II Cn 𝑅 ) ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ∃ ∈ ( II Cn 𝑆 ) ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) )
11 5 10 sylbir ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) → ( ∃ 𝑔 ∈ ( II Cn 𝑅 ) ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ∃ ∈ ( II Cn 𝑆 ) ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) )
12 reeanv ( ∃ 𝑔 ∈ ( II Cn 𝑅 ) ∃ ∈ ( II Cn 𝑆 ) ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ↔ ( ∃ 𝑔 ∈ ( II Cn 𝑅 ) ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ∃ ∈ ( II Cn 𝑆 ) ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) )
13 11 12 sylibr ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) → ∃ 𝑔 ∈ ( II Cn 𝑅 ) ∃ ∈ ( II Cn 𝑆 ) ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) )
14 iiuni ( 0 [,] 1 ) = II
15 eqid ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ )
16 14 15 txcnmpt ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) → ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) )
17 16 ad2antrl ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) )
18 0elunit 0 ∈ ( 0 [,] 1 )
19 fveq2 ( 𝑡 = 0 → ( 𝑔𝑡 ) = ( 𝑔 ‘ 0 ) )
20 fveq2 ( 𝑡 = 0 → ( 𝑡 ) = ( ‘ 0 ) )
21 19 20 opeq12d ( 𝑡 = 0 → ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ = ⟨ ( 𝑔 ‘ 0 ) , ( ‘ 0 ) ⟩ )
22 opex ⟨ ( 𝑔 ‘ 0 ) , ( ‘ 0 ) ⟩ ∈ V
23 21 15 22 fvmpt ( 0 ∈ ( 0 [,] 1 ) → ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ ( 𝑔 ‘ 0 ) , ( ‘ 0 ) ⟩ )
24 18 23 ax-mp ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ ( 𝑔 ‘ 0 ) , ( ‘ 0 ) ⟩
25 simprrl ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) )
26 25 simpld ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( 𝑔 ‘ 0 ) = 𝑥 )
27 simprrr ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) )
28 27 simpld ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ‘ 0 ) = 𝑦 )
29 26 28 opeq12d ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ⟨ ( 𝑔 ‘ 0 ) , ( ‘ 0 ) ⟩ = ⟨ 𝑥 , 𝑦 ⟩ )
30 24 29 eqtrid ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ )
31 1elunit 1 ∈ ( 0 [,] 1 )
32 fveq2 ( 𝑡 = 1 → ( 𝑔𝑡 ) = ( 𝑔 ‘ 1 ) )
33 fveq2 ( 𝑡 = 1 → ( 𝑡 ) = ( ‘ 1 ) )
34 32 33 opeq12d ( 𝑡 = 1 → ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ = ⟨ ( 𝑔 ‘ 1 ) , ( ‘ 1 ) ⟩ )
35 opex ⟨ ( 𝑔 ‘ 1 ) , ( ‘ 1 ) ⟩ ∈ V
36 34 15 35 fvmpt ( 1 ∈ ( 0 [,] 1 ) → ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ ( 𝑔 ‘ 1 ) , ( ‘ 1 ) ⟩ )
37 31 36 ax-mp ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ ( 𝑔 ‘ 1 ) , ( ‘ 1 ) ⟩
38 25 simprd ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( 𝑔 ‘ 1 ) = 𝑧 )
39 27 simprd ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ‘ 1 ) = 𝑤 )
40 38 39 opeq12d ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ⟨ ( 𝑔 ‘ 1 ) , ( ‘ 1 ) ⟩ = ⟨ 𝑧 , 𝑤 ⟩ )
41 37 40 eqtrid ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ )
42 fveq1 ( 𝑓 = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) → ( 𝑓 ‘ 0 ) = ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) )
43 42 eqeq1d ( 𝑓 = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) → ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ↔ ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ) )
44 fveq1 ( 𝑓 = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) → ( 𝑓 ‘ 1 ) = ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) )
45 44 eqeq1d ( 𝑓 = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) → ( ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ↔ ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
46 43 45 anbi12d ( 𝑓 = ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) → ( ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ↔ ( ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
47 46 rspcev ( ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ∧ ( ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( ( 𝑡 ∈ ( 0 [,] 1 ) ↦ ⟨ ( 𝑔𝑡 ) , ( 𝑡 ) ⟩ ) ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
48 17 30 41 47 syl12anc ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ∧ ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
49 48 expr ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) ∧ ( 𝑔 ∈ ( II Cn 𝑅 ) ∧ ∈ ( II Cn 𝑆 ) ) ) → ( ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
50 49 rexlimdvva ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) → ( ∃ 𝑔 ∈ ( II Cn 𝑅 ) ∃ ∈ ( II Cn 𝑆 ) ( ( ( 𝑔 ‘ 0 ) = 𝑥 ∧ ( 𝑔 ‘ 1 ) = 𝑧 ) ∧ ( ( ‘ 0 ) = 𝑦 ∧ ( ‘ 1 ) = 𝑤 ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
51 13 50 mpd ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
52 51 3expa ( ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ) ∧ ( 𝑧 𝑅𝑤 𝑆 ) ) → ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
53 52 ralrimivva ( ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) ∧ ( 𝑥 𝑅𝑦 𝑆 ) ) → ∀ 𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
54 53 ralrimivva ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ∀ 𝑥 𝑅𝑦 𝑆𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
55 eqeq2 ( 𝑣 = ⟨ 𝑧 , 𝑤 ⟩ → ( ( 𝑓 ‘ 1 ) = 𝑣 ↔ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
56 55 anbi2d ( 𝑣 = ⟨ 𝑧 , 𝑤 ⟩ → ( ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
57 56 rexbidv ( 𝑣 = ⟨ 𝑧 , 𝑤 ⟩ → ( ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
58 57 ralxp ( ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∀ 𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
59 eqeq2 ( 𝑢 = ⟨ 𝑥 , 𝑦 ⟩ → ( ( 𝑓 ‘ 0 ) = 𝑢 ↔ ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ) )
60 59 anbi1d ( 𝑢 = ⟨ 𝑥 , 𝑦 ⟩ → ( ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ↔ ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
61 60 rexbidv ( 𝑢 = ⟨ 𝑥 , 𝑦 ⟩ → ( ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ↔ ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
62 61 2ralbidv ( 𝑢 = ⟨ 𝑥 , 𝑦 ⟩ → ( ∀ 𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ↔ ∀ 𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
63 58 62 syl5bb ( 𝑢 = ⟨ 𝑥 , 𝑦 ⟩ → ( ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∀ 𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) ) )
64 63 ralxp ( ∀ 𝑢 ∈ ( 𝑅 × 𝑆 ) ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∀ 𝑥 𝑅𝑦 𝑆𝑧 𝑅𝑤 𝑆𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = ⟨ 𝑥 , 𝑦 ⟩ ∧ ( 𝑓 ‘ 1 ) = ⟨ 𝑧 , 𝑤 ⟩ ) )
65 54 64 sylibr ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ∀ 𝑢 ∈ ( 𝑅 × 𝑆 ) ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) )
66 6 8 txuni ( ( 𝑅 ∈ Top ∧ 𝑆 ∈ Top ) → ( 𝑅 × 𝑆 ) = ( 𝑅 ×t 𝑆 ) )
67 1 2 66 syl2an ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( 𝑅 × 𝑆 ) = ( 𝑅 ×t 𝑆 ) )
68 67 raleqdv ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∀ 𝑣 ( 𝑅 ×t 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ) )
69 67 68 raleqbidv ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( ∀ 𝑢 ∈ ( 𝑅 × 𝑆 ) ∀ 𝑣 ∈ ( 𝑅 × 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ↔ ∀ 𝑢 ( 𝑅 ×t 𝑆 ) ∀ 𝑣 ( 𝑅 ×t 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ) )
70 65 69 mpbid ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ∀ 𝑢 ( 𝑅 ×t 𝑆 ) ∀ 𝑣 ( 𝑅 ×t 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) )
71 eqid ( 𝑅 ×t 𝑆 ) = ( 𝑅 ×t 𝑆 )
72 71 ispconn ( ( 𝑅 ×t 𝑆 ) ∈ PConn ↔ ( ( 𝑅 ×t 𝑆 ) ∈ Top ∧ ∀ 𝑢 ( 𝑅 ×t 𝑆 ) ∀ 𝑣 ( 𝑅 ×t 𝑆 ) ∃ 𝑓 ∈ ( II Cn ( 𝑅 ×t 𝑆 ) ) ( ( 𝑓 ‘ 0 ) = 𝑢 ∧ ( 𝑓 ‘ 1 ) = 𝑣 ) ) )
73 4 70 72 sylanbrc ( ( 𝑅 ∈ PConn ∧ 𝑆 ∈ PConn ) → ( 𝑅 ×t 𝑆 ) ∈ PConn )