Metamath Proof Explorer


Theorem unxpdomlem3

Description: Lemma for unxpdom . (Contributed by Mario Carneiro, 13-Jan-2013) (Revised by Mario Carneiro, 16-Nov-2014)

Ref Expression
Hypotheses unxpdomlem1.1 𝐹 = ( 𝑥 ∈ ( 𝑎𝑏 ) ↦ 𝐺 )
unxpdomlem1.2 𝐺 = if ( 𝑥𝑎 , ⟨ 𝑥 , if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) , 𝑥 ⟩ )
Assertion unxpdomlem3 ( ( 1o𝑎 ∧ 1o𝑏 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )

Proof

Step Hyp Ref Expression
1 unxpdomlem1.1 𝐹 = ( 𝑥 ∈ ( 𝑎𝑏 ) ↦ 𝐺 )
2 unxpdomlem1.2 𝐺 = if ( 𝑥𝑎 , ⟨ 𝑥 , if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) , 𝑥 ⟩ )
3 1sdom ( 𝑎 ∈ V → ( 1o𝑎 ↔ ∃ 𝑚𝑎𝑛𝑎 ¬ 𝑚 = 𝑛 ) )
4 3 elv ( 1o𝑎 ↔ ∃ 𝑚𝑎𝑛𝑎 ¬ 𝑚 = 𝑛 )
5 1sdom ( 𝑏 ∈ V → ( 1o𝑏 ↔ ∃ 𝑠𝑏𝑡𝑏 ¬ 𝑠 = 𝑡 ) )
6 5 elv ( 1o𝑏 ↔ ∃ 𝑠𝑏𝑡𝑏 ¬ 𝑠 = 𝑡 )
7 reeanv ( ∃ 𝑚𝑎𝑠𝑏 ( ∃ 𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑡𝑏 ¬ 𝑠 = 𝑡 ) ↔ ( ∃ 𝑚𝑎𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑠𝑏𝑡𝑏 ¬ 𝑠 = 𝑡 ) )
8 reeanv ( ∃ 𝑛𝑎𝑡𝑏 ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ↔ ( ∃ 𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑡𝑏 ¬ 𝑠 = 𝑡 ) )
9 vex 𝑎 ∈ V
10 vex 𝑏 ∈ V
11 9 10 unex ( 𝑎𝑏 ) ∈ V
12 9 10 xpex ( 𝑎 × 𝑏 ) ∈ V
13 simpr ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ 𝑥𝑎 ) → 𝑥𝑎 )
14 simp2r ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝑡𝑏 )
15 simp1r ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝑠𝑏 )
16 14 15 ifcld ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ∈ 𝑏 )
17 16 ad2antrr ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ 𝑥𝑎 ) → if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ∈ 𝑏 )
18 13 17 opelxpd ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ 𝑥𝑎 ) → ⟨ 𝑥 , if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ⟩ ∈ ( 𝑎 × 𝑏 ) )
19 simp2l ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝑛𝑎 )
20 simp1l ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝑚𝑎 )
21 19 20 ifcld ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) ∈ 𝑎 )
22 21 ad2antrr ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ ¬ 𝑥𝑎 ) → if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) ∈ 𝑎 )
23 elun ( 𝑥 ∈ ( 𝑎𝑏 ) ↔ ( 𝑥𝑎𝑥𝑏 ) )
24 23 bilani ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) → ( 𝑥𝑎𝑥𝑏 ) )
25 24 orcanai ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ ¬ 𝑥𝑎 ) → 𝑥𝑏 )
26 22 25 opelxpd ( ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) ∧ ¬ 𝑥𝑎 ) → ⟨ if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) , 𝑥 ⟩ ∈ ( 𝑎 × 𝑏 ) )
27 18 26 ifclda ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) → if ( 𝑥𝑎 , ⟨ 𝑥 , if ( 𝑥 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑥 = 𝑡 , 𝑛 , 𝑚 ) , 𝑥 ⟩ ) ∈ ( 𝑎 × 𝑏 ) )
28 2 27 eqeltrid ( ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) ∧ 𝑥 ∈ ( 𝑎𝑏 ) ) → 𝐺 ∈ ( 𝑎 × 𝑏 ) )
29 28 1 fmptd ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝐹 : ( 𝑎𝑏 ) ⟶ ( 𝑎 × 𝑏 ) )
30 1 2 unxpdomlem1 ( 𝑧 ∈ ( 𝑎𝑏 ) → ( 𝐹𝑧 ) = if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) )
31 30 ad2antrl ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → ( 𝐹𝑧 ) = if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) )
32 iftrue ( 𝑧𝑎 → if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) = ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
33 32 adantr ( ( 𝑧𝑎𝑤𝑎 ) → if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) = ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
34 31 33 sylan9eq ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎𝑤𝑎 ) ) → ( 𝐹𝑧 ) = ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
35 1 2 unxpdomlem1 ( 𝑤 ∈ ( 𝑎𝑏 ) → ( 𝐹𝑤 ) = if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) )
36 35 ad2antll ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → ( 𝐹𝑤 ) = if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) )
37 iftrue ( 𝑤𝑎 → if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) = ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
38 37 adantl ( ( 𝑧𝑎𝑤𝑎 ) → if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) = ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
39 36 38 sylan9eq ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎𝑤𝑎 ) ) → ( 𝐹𝑤 ) = ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ )
40 34 39 eqeq12d ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ = ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ ) )
41 vex 𝑧 ∈ V
42 vex 𝑡 ∈ V
43 vex 𝑠 ∈ V
44 42 43 ifex if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ∈ V
45 41 44 opth1 ( ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ = ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ → 𝑧 = 𝑤 )
46 40 45 biimtrdi ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
47 simprr ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → 𝑤 ∈ ( 𝑎𝑏 ) )
48 simpll ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → ¬ 𝑚 = 𝑛 )
49 simplr ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → ¬ 𝑠 = 𝑡 )
50 1 2 47 48 49 unxpdomlem2 ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ¬ ( 𝐹𝑧 ) = ( 𝐹𝑤 ) )
51 50 pm2.21d ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
52 eqcom ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ ( 𝐹𝑤 ) = ( 𝐹𝑧 ) )
53 simprl ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → 𝑧 ∈ ( 𝑎𝑏 ) )
54 1 2 53 48 49 unxpdomlem2 ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( 𝑤𝑎 ∧ ¬ 𝑧𝑎 ) ) → ¬ ( 𝐹𝑤 ) = ( 𝐹𝑧 ) )
55 54 ancom2s ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎𝑤𝑎 ) ) → ¬ ( 𝐹𝑤 ) = ( 𝐹𝑧 ) )
56 55 pm2.21d ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎𝑤𝑎 ) ) → ( ( 𝐹𝑤 ) = ( 𝐹𝑧 ) → 𝑧 = 𝑤 ) )
57 52 56 biimtrid ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
58 iffalse ( ¬ 𝑧𝑎 → if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) = ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ )
59 58 adantr ( ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) → if ( 𝑧𝑎 , ⟨ 𝑧 , if ( 𝑧 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ ) = ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ )
60 31 59 sylan9eq ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ( 𝐹𝑧 ) = ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ )
61 iffalse ( ¬ 𝑤𝑎 → if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ )
62 61 adantl ( ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) → if ( 𝑤𝑎 , ⟨ 𝑤 , if ( 𝑤 = 𝑚 , 𝑡 , 𝑠 ) ⟩ , ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ )
63 36 62 sylan9eq ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ( 𝐹𝑤 ) = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ )
64 60 63 eqeq12d ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ) )
65 vex 𝑛 ∈ V
66 vex 𝑚 ∈ V
67 65 66 ifex if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) ∈ V
68 67 41 opth ( ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ ↔ ( if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) = if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) ∧ 𝑧 = 𝑤 ) )
69 68 simprbi ( ⟨ if ( 𝑧 = 𝑡 , 𝑛 , 𝑚 ) , 𝑧 ⟩ = ⟨ if ( 𝑤 = 𝑡 , 𝑛 , 𝑚 ) , 𝑤 ⟩ → 𝑧 = 𝑤 )
70 64 69 biimtrdi ( ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) ∧ ( ¬ 𝑧𝑎 ∧ ¬ 𝑤𝑎 ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
71 46 51 57 70 4casesdan ( ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ∧ ( 𝑧 ∈ ( 𝑎𝑏 ) ∧ 𝑤 ∈ ( 𝑎𝑏 ) ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
72 71 ralrimivva ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) → ∀ 𝑧 ∈ ( 𝑎𝑏 ) ∀ 𝑤 ∈ ( 𝑎𝑏 ) ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
73 72 3ad2ant3 ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → ∀ 𝑧 ∈ ( 𝑎𝑏 ) ∀ 𝑤 ∈ ( 𝑎𝑏 ) ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) )
74 dff13 ( 𝐹 : ( 𝑎𝑏 ) –1-1→ ( 𝑎 × 𝑏 ) ↔ ( 𝐹 : ( 𝑎𝑏 ) ⟶ ( 𝑎 × 𝑏 ) ∧ ∀ 𝑧 ∈ ( 𝑎𝑏 ) ∀ 𝑤 ∈ ( 𝑎𝑏 ) ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) → 𝑧 = 𝑤 ) ) )
75 29 73 74 sylanbrc ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → 𝐹 : ( 𝑎𝑏 ) –1-1→ ( 𝑎 × 𝑏 ) )
76 f1dom2g ( ( ( 𝑎𝑏 ) ∈ V ∧ ( 𝑎 × 𝑏 ) ∈ V ∧ 𝐹 : ( 𝑎𝑏 ) –1-1→ ( 𝑎 × 𝑏 ) ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )
77 11 12 75 76 mp3an12i ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ∧ ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )
78 77 3expia ( ( ( 𝑚𝑎𝑠𝑏 ) ∧ ( 𝑛𝑎𝑡𝑏 ) ) → ( ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) ) )
79 78 rexlimdvva ( ( 𝑚𝑎𝑠𝑏 ) → ( ∃ 𝑛𝑎𝑡𝑏 ( ¬ 𝑚 = 𝑛 ∧ ¬ 𝑠 = 𝑡 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) ) )
80 8 79 biimtrrid ( ( 𝑚𝑎𝑠𝑏 ) → ( ( ∃ 𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑡𝑏 ¬ 𝑠 = 𝑡 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) ) )
81 80 rexlimivv ( ∃ 𝑚𝑎𝑠𝑏 ( ∃ 𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑡𝑏 ¬ 𝑠 = 𝑡 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )
82 7 81 sylbir ( ( ∃ 𝑚𝑎𝑛𝑎 ¬ 𝑚 = 𝑛 ∧ ∃ 𝑠𝑏𝑡𝑏 ¬ 𝑠 = 𝑡 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )
83 4 6 82 syl2anb ( ( 1o𝑎 ∧ 1o𝑏 ) → ( 𝑎𝑏 ) ≼ ( 𝑎 × 𝑏 ) )