Metamath Proof Explorer


Theorem naddasslem1

Description: Lemma for naddass . Expand out the expression for natural addition of three arguments. (Contributed by Scott Fenton, 20-Jan-2025)

Ref Expression
Assertion naddasslem1 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = { 𝑥 ∈ On ∣ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) } )

Proof

Step Hyp Ref Expression
1 naddcl ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ) → ( 𝐴 +no 𝐵 ) ∈ On )
2 1 3adant3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( 𝐴 +no 𝐵 ) ∈ On )
3 simp3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → 𝐶 ∈ On )
4 naddov3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ) → ( 𝐴 +no 𝐵 ) = { 𝑎 ∈ On ∣ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) ⊆ 𝑎 } )
5 4 3adant3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( 𝐴 +no 𝐵 ) = { 𝑎 ∈ On ∣ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) ⊆ 𝑎 } )
6 intmin ( 𝐶 ∈ On → { 𝑐 ∈ On ∣ 𝐶𝑐 } = 𝐶 )
7 6 eqcomd ( 𝐶 ∈ On → 𝐶 = { 𝑐 ∈ On ∣ 𝐶𝑐 } )
8 7 3ad2ant3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → 𝐶 = { 𝑐 ∈ On ∣ 𝐶𝑐 } )
9 2 3 5 8 naddunif ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = { 𝑥 ∈ On ∣ ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 } )
10 df-3an ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) ↔ ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) )
11 unss ( ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) ↔ ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ∪ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ) ⊆ 𝑥 )
12 ancom ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) ↔ ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) )
13 xpundir ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) = ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ∪ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) )
14 13 imaeq2i ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) = ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ∪ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) )
15 imaundi ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ∪ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ) = ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ∪ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) )
16 14 15 eqtri ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) = ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ∪ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) )
17 16 sseq1i ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ∪ ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ) ⊆ 𝑥 )
18 11 12 17 3bitr4i ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) ↔ ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ⊆ 𝑥 )
19 18 anbi1i ( ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ) ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) ↔ ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) )
20 unss ( ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) ↔ ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 )
21 10 19 20 3bitrri ( ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 ↔ ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) )
22 naddfn +no Fn ( On × On )
23 fnfun ( +no Fn ( On × On ) → Fun +no )
24 22 23 ax-mp Fun +no
25 imassrn ( +no “ ( 𝐴 × { 𝐵 } ) ) ⊆ ran +no
26 naddf +no : ( On × On ) ⟶ On
27 frn ( +no : ( On × On ) ⟶ On → ran +no ⊆ On )
28 26 27 ax-mp ran +no ⊆ On
29 25 28 sstri ( +no “ ( 𝐴 × { 𝐵 } ) ) ⊆ On
30 simpl3 ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐶 ∈ On )
31 30 snssd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → { 𝐶 } ⊆ On )
32 xpss12 ( ( ( +no “ ( 𝐴 × { 𝐵 } ) ) ⊆ On ∧ { 𝐶 } ⊆ On ) → ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ⊆ ( On × On ) )
33 29 31 32 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ⊆ ( On × On ) )
34 22 fndmi dom +no = ( On × On )
35 33 34 sseqtrrdi ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ⊆ dom +no )
36 funimassov ( ( Fun +no ∧ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ⊆ dom +no ) → ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ) )
37 24 35 36 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ) )
38 oveq2 ( 𝑐 = 𝐶 → ( 𝑝 +no 𝑐 ) = ( 𝑝 +no 𝐶 ) )
39 38 eleq1d ( 𝑐 = 𝐶 → ( ( 𝑝 +no 𝑐 ) ∈ 𝑥 ↔ ( 𝑝 +no 𝐶 ) ∈ 𝑥 ) )
40 39 ralsng ( 𝐶 ∈ On → ( ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ↔ ( 𝑝 +no 𝐶 ) ∈ 𝑥 ) )
41 30 40 syl ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ↔ ( 𝑝 +no 𝐶 ) ∈ 𝑥 ) )
42 41 ralbidv ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ) )
43 onss ( 𝐴 ∈ On → 𝐴 ⊆ On )
44 43 3ad2ant1 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → 𝐴 ⊆ On )
45 44 adantr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐴 ⊆ On )
46 simpl2 ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐵 ∈ On )
47 46 snssd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → { 𝐵 } ⊆ On )
48 xpss12 ( ( 𝐴 ⊆ On ∧ { 𝐵 } ⊆ On ) → ( 𝐴 × { 𝐵 } ) ⊆ ( On × On ) )
49 45 47 48 syl2anc ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( 𝐴 × { 𝐵 } ) ⊆ ( On × On ) )
50 oveq1 ( 𝑝 = ( 𝑎 +no 𝑏 ) → ( 𝑝 +no 𝐶 ) = ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) )
51 50 eleq1d ( 𝑝 = ( 𝑎 +no 𝑏 ) → ( ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
52 51 imaeqalov ( ( +no Fn ( On × On ) ∧ ( 𝐴 × { 𝐵 } ) ⊆ ( On × On ) ) → ( ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎𝐴𝑏 ∈ { 𝐵 } ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
53 22 49 52 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎𝐴𝑏 ∈ { 𝐵 } ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
54 oveq2 ( 𝑏 = 𝐵 → ( 𝑎 +no 𝑏 ) = ( 𝑎 +no 𝐵 ) )
55 54 oveq1d ( 𝑏 = 𝐵 → ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) = ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) )
56 55 eleq1d ( 𝑏 = 𝐵 → ( ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
57 56 ralsng ( 𝐵 ∈ On → ( ∀ 𝑏 ∈ { 𝐵 } ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
58 46 57 syl ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑏 ∈ { 𝐵 } ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
59 58 ralbidv ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑎𝐴𝑏 ∈ { 𝐵 } ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
60 53 59 bitrd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( 𝐴 × { 𝐵 } ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
61 37 42 60 3bitrd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ) )
62 imassrn ( +no “ ( { 𝐴 } × 𝐵 ) ) ⊆ ran +no
63 62 28 sstri ( +no “ ( { 𝐴 } × 𝐵 ) ) ⊆ On
64 xpss12 ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ⊆ On ∧ { 𝐶 } ⊆ On ) → ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ⊆ ( On × On ) )
65 63 31 64 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ⊆ ( On × On ) )
66 65 34 sseqtrrdi ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ⊆ dom +no )
67 funimassov ( ( Fun +no ∧ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ⊆ dom +no ) → ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ) )
68 24 66 67 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ) )
69 41 ralbidv ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ∀ 𝑐 ∈ { 𝐶 } ( 𝑝 +no 𝑐 ) ∈ 𝑥 ↔ ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ) )
70 simpl1 ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐴 ∈ On )
71 70 snssd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → { 𝐴 } ⊆ On )
72 onss ( 𝐵 ∈ On → 𝐵 ⊆ On )
73 72 3ad2ant2 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → 𝐵 ⊆ On )
74 73 adantr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐵 ⊆ On )
75 xpss12 ( ( { 𝐴 } ⊆ On ∧ 𝐵 ⊆ On ) → ( { 𝐴 } × 𝐵 ) ⊆ ( On × On ) )
76 71 74 75 syl2anc ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( { 𝐴 } × 𝐵 ) ⊆ ( On × On ) )
77 51 imaeqalov ( ( +no Fn ( On × On ) ∧ ( { 𝐴 } × 𝐵 ) ⊆ ( On × On ) ) → ( ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎 ∈ { 𝐴 } ∀ 𝑏𝐵 ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
78 22 76 77 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑎 ∈ { 𝐴 } ∀ 𝑏𝐵 ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
79 oveq1 ( 𝑎 = 𝐴 → ( 𝑎 +no 𝑏 ) = ( 𝐴 +no 𝑏 ) )
80 79 oveq1d ( 𝑎 = 𝐴 → ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) = ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) )
81 80 eleq1d ( 𝑎 = 𝐴 → ( ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
82 81 ralbidv ( 𝑎 = 𝐴 → ( ∀ 𝑏𝐵 ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
83 82 ralsng ( 𝐴 ∈ On → ( ∀ 𝑎 ∈ { 𝐴 } ∀ 𝑏𝐵 ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
84 70 83 syl ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑎 ∈ { 𝐴 } ∀ 𝑏𝐵 ( ( 𝑎 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
85 78 84 bitrd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ∀ 𝑝 ∈ ( +no “ ( { 𝐴 } × 𝐵 ) ) ( 𝑝 +no 𝐶 ) ∈ 𝑥 ↔ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
86 68 69 85 3bitrd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ↔ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ) )
87 2 adantr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( 𝐴 +no 𝐵 ) ∈ On )
88 87 snssd ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → { ( 𝐴 +no 𝐵 ) } ⊆ On )
89 onss ( 𝐶 ∈ On → 𝐶 ⊆ On )
90 89 3ad2ant3 ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → 𝐶 ⊆ On )
91 90 adantr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → 𝐶 ⊆ On )
92 xpss12 ( ( { ( 𝐴 +no 𝐵 ) } ⊆ On ∧ 𝐶 ⊆ On ) → ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ⊆ ( On × On ) )
93 88 91 92 syl2anc ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ⊆ ( On × On ) )
94 93 34 sseqtrrdi ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ⊆ dom +no )
95 funimassov ( ( Fun +no ∧ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ⊆ dom +no ) → ( ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ↔ ∀ 𝑎 ∈ { ( 𝐴 +no 𝐵 ) } ∀ 𝑐𝐶 ( 𝑎 +no 𝑐 ) ∈ 𝑥 ) )
96 24 94 95 sylancr ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ↔ ∀ 𝑎 ∈ { ( 𝐴 +no 𝐵 ) } ∀ 𝑐𝐶 ( 𝑎 +no 𝑐 ) ∈ 𝑥 ) )
97 ovex ( 𝐴 +no 𝐵 ) ∈ V
98 oveq1 ( 𝑎 = ( 𝐴 +no 𝐵 ) → ( 𝑎 +no 𝑐 ) = ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) )
99 98 eleq1d ( 𝑎 = ( 𝐴 +no 𝐵 ) → ( ( 𝑎 +no 𝑐 ) ∈ 𝑥 ↔ ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) )
100 99 ralbidv ( 𝑎 = ( 𝐴 +no 𝐵 ) → ( ∀ 𝑐𝐶 ( 𝑎 +no 𝑐 ) ∈ 𝑥 ↔ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) )
101 97 100 ralsn ( ∀ 𝑎 ∈ { ( 𝐴 +no 𝐵 ) } ∀ 𝑐𝐶 ( 𝑎 +no 𝑐 ) ∈ 𝑥 ↔ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 )
102 96 101 bitrdi ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ↔ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) )
103 61 86 102 3anbi123d ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( ( +no “ ( ( +no “ ( 𝐴 × { 𝐵 } ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( ( +no “ ( { 𝐴 } × 𝐵 ) ) × { 𝐶 } ) ) ⊆ 𝑥 ∧ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ⊆ 𝑥 ) ↔ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) ) )
104 21 103 bitrid ( ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) ∧ 𝑥 ∈ On ) → ( ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 ↔ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) ) )
105 104 rabbidva ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → { 𝑥 ∈ On ∣ ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 } = { 𝑥 ∈ On ∣ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) } )
106 105 inteqd ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → { 𝑥 ∈ On ∣ ( ( +no “ ( ( ( +no “ ( { 𝐴 } × 𝐵 ) ) ∪ ( +no “ ( 𝐴 × { 𝐵 } ) ) ) × { 𝐶 } ) ) ∪ ( +no “ ( { ( 𝐴 +no 𝐵 ) } × 𝐶 ) ) ) ⊆ 𝑥 } = { 𝑥 ∈ On ∣ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) } )
107 9 106 eqtrd ( ( 𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On ) → ( ( 𝐴 +no 𝐵 ) +no 𝐶 ) = { 𝑥 ∈ On ∣ ( ∀ 𝑎𝐴 ( ( 𝑎 +no 𝐵 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑏𝐵 ( ( 𝐴 +no 𝑏 ) +no 𝐶 ) ∈ 𝑥 ∧ ∀ 𝑐𝐶 ( ( 𝐴 +no 𝐵 ) +no 𝑐 ) ∈ 𝑥 ) } )