Metamath Proof Explorer


Theorem naddass

Description: Natural ordinal addition is associative. (Contributed by Scott Fenton, 20-Jan-2025)

Ref Expression
Assertion naddass ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = ( 𝐴 +no ( 𝐵 +no 𝐶 ) ) )

Proof

Step Hyp Ref Expression
1 oveq1 ( 𝑎 = 𝑥 → ( 𝑎 +no 𝑏 ) = ( 𝑥 +no 𝑏 ) )
2 1 oveq1d ( 𝑎 = 𝑥 → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) )
3 oveq1 ( 𝑎 = 𝑥 → ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) )
4 2 3 eqeq12d ( 𝑎 = 𝑥 → ( ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) ↔ ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ) )
5 oveq2 ( 𝑏 = 𝑦 → ( 𝑥 +no 𝑏 ) = ( 𝑥 +no 𝑦 ) )
6 5 oveq1d ( 𝑏 = 𝑦 → ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) )
7 oveq1 ( 𝑏 = 𝑦 → ( 𝑏 +no 𝑐 ) = ( 𝑦 +no 𝑐 ) )
8 7 oveq2d ( 𝑏 = 𝑦 → ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) )
9 6 8 eqeq12d ( 𝑏 = 𝑦 → ( ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ↔ ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ) )
10 oveq2 ( 𝑐 = 𝑧 → ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) )
11 oveq2 ( 𝑐 = 𝑧 → ( 𝑦 +no 𝑐 ) = ( 𝑦 +no 𝑧 ) )
12 11 oveq2d ( 𝑐 = 𝑧 → ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) )
13 10 12 eqeq12d ( 𝑐 = 𝑧 → ( ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ↔ ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ) )
14 oveq1 ( 𝑎 = 𝑥 → ( 𝑎 +no 𝑦 ) = ( 𝑥 +no 𝑦 ) )
15 14 oveq1d ( 𝑎 = 𝑥 → ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) )
16 oveq1 ( 𝑎 = 𝑥 → ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) )
17 15 16 eqeq12d ( 𝑎 = 𝑥 → ( ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ↔ ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ) )
18 oveq2 ( 𝑏 = 𝑦 → ( 𝑎 +no 𝑏 ) = ( 𝑎 +no 𝑦 ) )
19 18 oveq1d ( 𝑏 = 𝑦 → ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) )
20 oveq1 ( 𝑏 = 𝑦 → ( 𝑏 +no 𝑧 ) = ( 𝑦 +no 𝑧 ) )
21 20 oveq2d ( 𝑏 = 𝑦 → ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) )
22 19 21 eqeq12d ( 𝑏 = 𝑦 → ( ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ↔ ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ) )
23 5 oveq1d ( 𝑏 = 𝑦 → ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) )
24 20 oveq2d ( 𝑏 = 𝑦 → ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) )
25 23 24 eqeq12d ( 𝑏 = 𝑦 → ( ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ↔ ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ) )
26 oveq2 ( 𝑐 = 𝑧 → ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) )
27 11 oveq2d ( 𝑐 = 𝑧 → ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) )
28 26 27 eqeq12d ( 𝑐 = 𝑧 → ( ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ↔ ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ) )
29 oveq1 ( 𝑎 = 𝐴 → ( 𝑎 +no 𝑏 ) = ( 𝐴 +no 𝑏 ) )
30 29 oveq1d ( 𝑎 = 𝐴 → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( ( 𝐴 +no 𝑏 ) +no 𝑐 ) )
31 oveq1 ( 𝑎 = 𝐴 → ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) = ( 𝐴 +no ( 𝑏 +no 𝑐 ) ) )
32 30 31 eqeq12d ( 𝑎 = 𝐴 → ( ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) ↔ ( ( 𝐴 +no 𝑏 ) +no 𝑐 ) = ( 𝐴 +no ( 𝑏 +no 𝑐 ) ) ) )
33 oveq2 ( 𝑏 = 𝐵 → ( 𝐴 +no 𝑏 ) = ( 𝐴 +no 𝐵 ) )
34 33 oveq1d ( 𝑏 = 𝐵 → ( ( 𝐴 +no 𝑏 ) +no 𝑐 ) = ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) )
35 oveq1 ( 𝑏 = 𝐵 → ( 𝑏 +no 𝑐 ) = ( 𝐵 +no 𝑐 ) )
36 35 oveq2d ( 𝑏 = 𝐵 → ( 𝐴 +no ( 𝑏 +no 𝑐 ) ) = ( 𝐴 +no ( 𝐵 +no 𝑐 ) ) )
37 34 36 eqeq12d ( 𝑏 = 𝐵 → ( ( ( 𝐴 +no 𝑏 ) +no 𝑐 ) = ( 𝐴 +no ( 𝑏 +no 𝑐 ) ) ↔ ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) = ( 𝐴 +no ( 𝐵 +no 𝑐 ) ) ) )
38 oveq2 ( 𝑐 = 𝐶 → ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) = ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) )
39 oveq2 ( 𝑐 = 𝐶 → ( 𝐵 +no 𝑐 ) = ( 𝐵 +no 𝐶 ) )
40 39 oveq2d ( 𝑐 = 𝐶 → ( 𝐴 +no ( 𝐵 +no 𝑐 ) ) = ( 𝐴 +no ( 𝐵 +no 𝐶 ) ) )
41 38 40 eqeq12d ( 𝑐 = 𝐶 → ( ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) = ( 𝐴 +no ( 𝐵 +no 𝑐 ) ) ↔ ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = ( 𝐴 +no ( 𝐵 +no 𝐶 ) ) ) )
42 simpr21 ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) )
43 eleq1 ( ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) → ( ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ) )
44 43 ralimi ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) → ∀ 𝑥𝑎 ( ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ) )
45 ralbi ( ∀ 𝑥𝑎 ( ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ) → ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ↔ ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ) )
46 42 44 45 3syl ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ↔ ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ) )
47 simpr23 ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) )
48 eleq1 ( ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) → ( ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ) )
49 48 ralimi ( ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) → ∀ 𝑦𝑏 ( ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ) )
50 ralbi ( ∀ 𝑦𝑏 ( ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ) → ( ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ↔ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ) )
51 47 49 50 3syl ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ↔ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ) )
52 simpr3 ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) )
53 eleq1 ( ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) → ( ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) )
54 53 ralimi ( ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) → ∀ 𝑧𝑐 ( ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) )
55 ralbi ( ∀ 𝑧𝑐 ( ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ↔ ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) → ( ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ↔ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) )
56 52 54 55 3syl ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ↔ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) )
57 46 51 56 3anbi123d ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ) ↔ ( ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) ) )
58 57 rabbidv ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ) } = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) } )
59 58 inteqd ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ) } = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) } )
60 naddasslem1 ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ) } )
61 60 adantr ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) ∈ 𝑤 ) } )
62 naddasslem2 ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) → ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) } )
63 62 adantr ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) = { 𝑤 ∈ On ∣ ( ∀ 𝑥𝑎 ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑦𝑏 ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ∈ 𝑤 ∧ ∀ 𝑧𝑐 ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ∈ 𝑤 ) } )
64 59 61 63 3eqtr4d ( ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) ∧ ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) ) → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) )
65 64 ex ( ( 𝑎 ∈ On ∧ 𝑏 ∈ On ∧ 𝑐 ∈ On ) → ( ( ( ∀ 𝑥𝑎𝑦𝑏𝑧𝑐 ( ( 𝑥 +no 𝑦 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑥𝑎𝑦𝑏 ( ( 𝑥 +no 𝑦 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑦 +no 𝑐 ) ) ∧ ∀ 𝑥𝑎𝑧𝑐 ( ( 𝑥 +no 𝑏 ) +no 𝑧 ) = ( 𝑥 +no ( 𝑏 +no 𝑧 ) ) ) ∧ ( ∀ 𝑥𝑎 ( ( 𝑥 +no 𝑏 ) +no 𝑐 ) = ( 𝑥 +no ( 𝑏 +no 𝑐 ) ) ∧ ∀ 𝑦𝑏𝑧𝑐 ( ( 𝑎 +no 𝑦 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑦 +no 𝑧 ) ) ∧ ∀ 𝑦𝑏 ( ( 𝑎 +no 𝑦 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑦 +no 𝑐 ) ) ) ∧ ∀ 𝑧𝑐 ( ( 𝑎 +no 𝑏 ) +no 𝑧 ) = ( 𝑎 +no ( 𝑏 +no 𝑧 ) ) ) → ( ( 𝑎 +no 𝑏 ) +no 𝑐 ) = ( 𝑎 +no ( 𝑏 +no 𝑐 ) ) ) )
66 4 9 13 17 22 25 28 32 37 41 65 on3ind ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = ( 𝐴 +no ( 𝐵 +no 𝐶 ) ) )