Metamath Proof Explorer


Theorem fmlasuc

Description: The valid Godel formulas of height ( N + 1 ) , expressed by the valid Godel formulas of height N . (Contributed by AV, 20-Sep-2023)

Ref Expression
Assertion fmlasuc ⊢ N ∈ ω → Fmla ⁡ suc ⁡ N = Fmla ⁡ N ∪ x | ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u

Proof

Step Hyp Ref Expression
1 fmlasuc0 ⊢ N ∈ ω → Fmla ⁡ suc ⁡ N = Fmla ⁡ N ∪ x | ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
2 eqid ⊢ ∅ Sat ∅ = ∅ Sat ∅
3 2 satf0op ⊢ N ∈ ω → y ∈ ∅ Sat ∅ ⁡ N ↔ ∃ z y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N
4 fveq2 ⊢ z = w → 1 st ⁡ z = 1 st ⁡ w
5 4 oveq2d ⊢ z = w → 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w
6 5 eqeq2d ⊢ z = w → x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ↔ x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w
7 6 cbvrexvw ⊢ ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ↔ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w
8 7 orbi1i ⊢ ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ↔ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
9 fmlafvel ⊢ N ∈ ω → z ∈ Fmla ⁡ N ↔ z ∅ ∈ ∅ Sat ∅ ⁡ N
10 9 biimprd ⊢ N ∈ ω → z ∅ ∈ ∅ Sat ∅ ⁡ N → z ∈ Fmla ⁡ N
11 10 adantld ⊢ N ∈ ω → y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → z ∈ Fmla ⁡ N
12 11 imp ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → z ∈ Fmla ⁡ N
13 vex ⊢ z ∈ V
14 0ex ⊢ ∅ ∈ V
15 13 14 op1std ⊢ y = z ∅ → 1 st ⁡ y = z
16 15 eleq1d ⊢ y = z ∅ → 1 st ⁡ y ∈ Fmla ⁡ N ↔ z ∈ Fmla ⁡ N
17 16 ad2antrl ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → 1 st ⁡ y ∈ Fmla ⁡ N ↔ z ∈ Fmla ⁡ N
18 12 17 mpbird ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → 1 st ⁡ y ∈ Fmla ⁡ N
19 18 3adant3 ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N ∧ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → 1 st ⁡ y ∈ Fmla ⁡ N
20 oveq1 ⊢ u = 1 st ⁡ y → u ⊼ 𝑔 v = 1 st ⁡ y ⊼ 𝑔 v
21 20 eqeq2d ⊢ u = 1 st ⁡ y → x = u ⊼ 𝑔 v ↔ x = 1 st ⁡ y ⊼ 𝑔 v
22 21 rexbidv ⊢ u = 1 st ⁡ y → ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ↔ ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v
23 eqidd ⊢ u = 1 st ⁡ y → i = i
24 id ⊢ u = 1 st ⁡ y → u = 1 st ⁡ y
25 23 24 goaleq12d ⊢ u = 1 st ⁡ y → ∀ 𝑔 i u = ∀ 𝑔 i 1 st ⁡ y
26 25 eqeq2d ⊢ u = 1 st ⁡ y → x = ∀ 𝑔 i u ↔ x = ∀ 𝑔 i 1 st ⁡ y
27 26 rexbidv ⊢ u = 1 st ⁡ y → ∃ i ∈ ω x = ∀ 𝑔 i u ↔ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
28 22 27 orbi12d ⊢ u = 1 st ⁡ y → ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u ↔ ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
29 28 adantl ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N ∧ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ∧ u = 1 st ⁡ y → ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u ↔ ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
30 2 satf0op ⊢ N ∈ ω → w ∈ ∅ Sat ∅ ⁡ N ↔ ∃ y w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N
31 fmlafvel ⊢ N ∈ ω → y ∈ Fmla ⁡ N ↔ y ∅ ∈ ∅ Sat ∅ ⁡ N
32 31 biimprd ⊢ N ∈ ω → y ∅ ∈ ∅ Sat ∅ ⁡ N → y ∈ Fmla ⁡ N
33 32 adantld ⊢ N ∈ ω → w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → y ∈ Fmla ⁡ N
34 33 imp ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → y ∈ Fmla ⁡ N
35 vex ⊢ y ∈ V
36 35 14 op1std ⊢ w = y ∅ → 1 st ⁡ w = y
37 36 eleq1d ⊢ w = y ∅ → 1 st ⁡ w ∈ Fmla ⁡ N ↔ y ∈ Fmla ⁡ N
38 37 ad2antrl ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → 1 st ⁡ w ∈ Fmla ⁡ N ↔ y ∈ Fmla ⁡ N
39 34 38 mpbird ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → 1 st ⁡ w ∈ Fmla ⁡ N
40 39 adantr ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N ∧ x = z ⊼ 𝑔 1 st ⁡ w → 1 st ⁡ w ∈ Fmla ⁡ N
41 oveq2 ⊢ v = 1 st ⁡ w → z ⊼ 𝑔 v = z ⊼ 𝑔 1 st ⁡ w
42 41 eqeq2d ⊢ v = 1 st ⁡ w → x = z ⊼ 𝑔 v ↔ x = z ⊼ 𝑔 1 st ⁡ w
43 42 adantl ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N ∧ x = z ⊼ 𝑔 1 st ⁡ w ∧ v = 1 st ⁡ w → x = z ⊼ 𝑔 v ↔ x = z ⊼ 𝑔 1 st ⁡ w
44 simpr ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N ∧ x = z ⊼ 𝑔 1 st ⁡ w → x = z ⊼ 𝑔 1 st ⁡ w
45 40 43 44 rspcedvd ⊢ N ∈ ω ∧ w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N ∧ x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
46 45 exp31 ⊢ N ∈ ω → w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
47 46 exlimdv ⊢ N ∈ ω → ∃ y w = y ∅ ∧ y ∅ ∈ ∅ Sat ∅ ⁡ N → x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
48 30 47 sylbid ⊢ N ∈ ω → w ∈ ∅ Sat ∅ ⁡ N → x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
49 48 rexlimdv ⊢ N ∈ ω → ∃ w ∈ ∅ Sat ∅ ⁡ N x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
50 49 adantr ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
51 15 oveq1d ⊢ y = z ∅ → 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w = z ⊼ 𝑔 1 st ⁡ w
52 51 eqeq2d ⊢ y = z ∅ → x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ↔ x = z ⊼ 𝑔 1 st ⁡ w
53 52 rexbidv ⊢ y = z ∅ → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ↔ ∃ w ∈ ∅ Sat ∅ ⁡ N x = z ⊼ 𝑔 1 st ⁡ w
54 15 oveq1d ⊢ y = z ∅ → 1 st ⁡ y ⊼ 𝑔 v = z ⊼ 𝑔 v
55 54 eqeq2d ⊢ y = z ∅ → x = 1 st ⁡ y ⊼ 𝑔 v ↔ x = z ⊼ 𝑔 v
56 55 rexbidv ⊢ y = z ∅ → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ↔ ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
57 53 56 imbi12d ⊢ y = z ∅ → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ↔ ∃ w ∈ ∅ Sat ∅ ⁡ N x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
58 57 ad2antrl ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ↔ ∃ w ∈ ∅ Sat ∅ ⁡ N x = z ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = z ⊼ 𝑔 v
59 50 58 mpbird ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v
60 59 orim1d ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
61 60 3impia ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N ∧ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ v ∈ Fmla ⁡ N x = 1 st ⁡ y ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
62 19 29 61 rspcedvd ⊢ N ∈ ω ∧ y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N ∧ ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
63 62 3exp ⊢ N ∈ ω → y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
64 63 exlimdv ⊢ N ∈ ω → ∃ z y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ w ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ w ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
65 8 64 syl7bi ⊢ N ∈ ω → ∃ z y = z ∅ ∧ z ∅ ∈ ∅ Sat ∅ ⁡ N → ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
66 3 65 sylbid ⊢ N ∈ ω → y ∈ ∅ Sat ∅ ⁡ N → ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
67 66 rexlimdv ⊢ N ∈ ω → ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
68 fmlafvel ⊢ N ∈ ω → u ∈ Fmla ⁡ N ↔ u ∅ ∈ ∅ Sat ∅ ⁡ N
69 68 biimpa ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N → u ∅ ∈ ∅ Sat ∅ ⁡ N
70 69 adantr ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u → u ∅ ∈ ∅ Sat ∅ ⁡ N
71 vex ⊢ u ∈ V
72 71 14 op1std ⊢ y = u ∅ → 1 st ⁡ y = u
73 72 oveq1d ⊢ y = u ∅ → 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z = u ⊼ 𝑔 1 st ⁡ z
74 73 eqeq2d ⊢ y = u ∅ → x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ↔ x = u ⊼ 𝑔 1 st ⁡ z
75 74 rexbidv ⊢ y = u ∅ → ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ↔ ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z
76 eqidd ⊢ y = u ∅ → i = i
77 76 72 goaleq12d ⊢ y = u ∅ → ∀ 𝑔 i 1 st ⁡ y = ∀ 𝑔 i u
78 77 eqeq2d ⊢ y = u ∅ → x = ∀ 𝑔 i 1 st ⁡ y ↔ x = ∀ 𝑔 i u
79 78 rexbidv ⊢ y = u ∅ → ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ↔ ∃ i ∈ ω x = ∀ 𝑔 i u
80 75 79 orbi12d ⊢ y = u ∅ → ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ↔ ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
81 80 adantl ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u ∧ y = u ∅ → ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ↔ ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
82 fmlafvel ⊢ N ∈ ω → v ∈ Fmla ⁡ N ↔ v ∅ ∈ ∅ Sat ∅ ⁡ N
83 82 biimpd ⊢ N ∈ ω → v ∈ Fmla ⁡ N → v ∅ ∈ ∅ Sat ∅ ⁡ N
84 83 adantr ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N → v ∈ Fmla ⁡ N → v ∅ ∈ ∅ Sat ∅ ⁡ N
85 84 imp ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ v ∈ Fmla ⁡ N → v ∅ ∈ ∅ Sat ∅ ⁡ N
86 85 adantr ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ v ∈ Fmla ⁡ N ∧ x = u ⊼ 𝑔 v → v ∅ ∈ ∅ Sat ∅ ⁡ N
87 vex ⊢ v ∈ V
88 87 14 op1std ⊢ z = v ∅ → 1 st ⁡ z = v
89 88 oveq2d ⊢ z = v ∅ → u ⊼ 𝑔 1 st ⁡ z = u ⊼ 𝑔 v
90 89 eqeq2d ⊢ z = v ∅ → x = u ⊼ 𝑔 1 st ⁡ z ↔ x = u ⊼ 𝑔 v
91 90 adantl ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ v ∈ Fmla ⁡ N ∧ x = u ⊼ 𝑔 v ∧ z = v ∅ → x = u ⊼ 𝑔 1 st ⁡ z ↔ x = u ⊼ 𝑔 v
92 simpr ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ v ∈ Fmla ⁡ N ∧ x = u ⊼ 𝑔 v → x = u ⊼ 𝑔 v
93 86 91 92 rspcedvd ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ v ∈ Fmla ⁡ N ∧ x = u ⊼ 𝑔 v → ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z
94 93 rexlimdva2 ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N → ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v → ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z
95 94 orim1d ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N → ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u → ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
96 95 imp ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u → ∃ z ∈ ∅ Sat ∅ ⁡ N x = u ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
97 70 81 96 rspcedvd ⊢ N ∈ ω ∧ u ∈ Fmla ⁡ N ∧ ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u → ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
98 97 rexlimdva2 ⊢ N ∈ ω → ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u → ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y
99 67 98 impbid ⊢ N ∈ ω → ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y ↔ ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
100 99 abbidv ⊢ N ∈ ω → x | ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y = x | ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
101 100 uneq2d ⊢ N ∈ ω → Fmla ⁡ N ∪ x | ∃ y ∈ ∅ Sat ∅ ⁡ N ∃ z ∈ ∅ Sat ∅ ⁡ N x = 1 st ⁡ y ⊼ 𝑔 1 st ⁡ z ∨ ∃ i ∈ ω x = ∀ 𝑔 i 1 st ⁡ y = Fmla ⁡ N ∪ x | ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u
102 1 101 eqtrd ⊢ N ∈ ω → Fmla ⁡ suc ⁡ N = Fmla ⁡ N ∪ x | ∃ u ∈ Fmla ⁡ N ∃ v ∈ Fmla ⁡ N x = u ⊼ 𝑔 v ∨ ∃ i ∈ ω x = ∀ 𝑔 i u