| Step | Hyp | Ref
 | Expression | 
| 1 |   | ncfinlowerlem1 4483 | 
. . . 4
⊢ {m ∣ ∀a∀b((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))} ∈
V | 
| 2 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = 0c → (℘1a ∈ m ↔ ℘1a ∈
0c)) | 
| 3 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = 0c → (℘1b ∈ m ↔ ℘1b ∈
0c)) | 
| 4 | 2, 3 | anbi12d 691 | 
. . . . . 6
⊢ (m = 0c → ((℘1a ∈ m ∧ ℘1b ∈ m) ↔ (℘1a ∈
0c ∧ ℘1b ∈
0c))) | 
| 5 | 4 | imbi1d 308 | 
. . . . 5
⊢ (m = 0c → (((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1a ∈
0c ∧ ℘1b ∈
0c) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 6 | 5 | 2albidv 1627 | 
. . . 4
⊢ (m = 0c → (∀a∀b((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ∀a∀b((℘1a ∈
0c ∧ ℘1b ∈
0c) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 7 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = k →
(℘1a ∈ m ↔ ℘1a ∈ k)) | 
| 8 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = k →
(℘1b ∈ m ↔ ℘1b ∈ k)) | 
| 9 | 7, 8 | anbi12d 691 | 
. . . . . 6
⊢ (m = k →
((℘1a ∈ m ∧ ℘1b ∈ m) ↔ (℘1a ∈ k ∧ ℘1b ∈ k))) | 
| 10 | 9 | imbi1d 308 | 
. . . . 5
⊢ (m = k →
(((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 11 | 10 | 2albidv 1627 | 
. . . 4
⊢ (m = k →
(∀a∀b((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 12 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = (k
+c 1c) → (℘1a ∈ m ↔ ℘1a ∈ (k +c
1c))) | 
| 13 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = (k
+c 1c) → (℘1b ∈ m ↔ ℘1b ∈ (k +c
1c))) | 
| 14 | 12, 13 | anbi12d 691 | 
. . . . . 6
⊢ (m = (k
+c 1c) → ((℘1a ∈ m ∧ ℘1b ∈ m) ↔ (℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c
1c)))) | 
| 15 | 14 | imbi1d 308 | 
. . . . 5
⊢ (m = (k
+c 1c) → (((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 16 | 15 | 2albidv 1627 | 
. . . 4
⊢ (m = (k
+c 1c) → (∀a∀b((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ∀a∀b((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 17 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = M →
(℘1a ∈ m ↔ ℘1a ∈ M)) | 
| 18 |   | eleq2 2414 | 
. . . . . . 7
⊢ (m = M →
(℘1b ∈ m ↔ ℘1b ∈ M)) | 
| 19 | 17, 18 | anbi12d 691 | 
. . . . . 6
⊢ (m = M →
((℘1a ∈ m ∧ ℘1b ∈ m) ↔ (℘1a ∈ M ∧ ℘1b ∈ M))) | 
| 20 | 19 | imbi1d 308 | 
. . . . 5
⊢ (m = M →
(((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 21 | 20 | 2albidv 1627 | 
. . . 4
⊢ (m = M →
(∀a∀b((℘1a ∈ m ∧ ℘1b ∈ m) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ∀a∀b((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 22 |   | el0c 4422 | 
. . . . . . 7
⊢ (℘1a ∈
0c ↔ ℘1a = ∅) | 
| 23 |   | pw10b 4167 | 
. . . . . . 7
⊢ (℘1a = ∅ ↔
a = ∅) | 
| 24 | 22, 23 | bitri 240 | 
. . . . . 6
⊢ (℘1a ∈
0c ↔ a = ∅) | 
| 25 |   | el0c 4422 | 
. . . . . . 7
⊢ (℘1b ∈
0c ↔ ℘1b = ∅) | 
| 26 |   | pw10b 4167 | 
. . . . . . 7
⊢ (℘1b = ∅ ↔
b = ∅) | 
| 27 | 25, 26 | bitri 240 | 
. . . . . 6
⊢ (℘1b ∈
0c ↔ b = ∅) | 
| 28 |   | peano1 4403 | 
. . . . . . . 8
⊢
0c ∈ Nn | 
| 29 |   | nulel0c 4423 | 
. . . . . . . 8
⊢ ∅ ∈
0c | 
| 30 |   | eleq2 2414 | 
. . . . . . . . 9
⊢ (n = 0c → (∅ ∈ n ↔ ∅ ∈ 0c)) | 
| 31 | 30 | rspcev 2956 | 
. . . . . . . 8
⊢
((0c ∈ Nn ∧ ∅ ∈
0c) → ∃n ∈ Nn ∅ ∈ n) | 
| 32 | 28, 29, 31 | mp2an 653 | 
. . . . . . 7
⊢ ∃n ∈ Nn ∅ ∈ n | 
| 33 |   | eleq1 2413 | 
. . . . . . . . . 10
⊢ (a = ∅ →
(a ∈
n ↔ ∅ ∈ n)) | 
| 34 |   | eleq1 2413 | 
. . . . . . . . . 10
⊢ (b = ∅ →
(b ∈
n ↔ ∅ ∈ n)) | 
| 35 | 33, 34 | bi2anan9 843 | 
. . . . . . . . 9
⊢ ((a = ∅ ∧ b = ∅) → ((a
∈ n ∧ b ∈ n) ↔
(∅ ∈
n ∧ ∅ ∈ n))) | 
| 36 |   | anidm 625 | 
. . . . . . . . 9
⊢ ((∅ ∈ n ∧ ∅ ∈ n) ↔ ∅ ∈ n) | 
| 37 | 35, 36 | syl6bb 252 | 
. . . . . . . 8
⊢ ((a = ∅ ∧ b = ∅) → ((a
∈ n ∧ b ∈ n) ↔
∅ ∈
n)) | 
| 38 | 37 | rexbidv 2636 | 
. . . . . . 7
⊢ ((a = ∅ ∧ b = ∅) → (∃n ∈ Nn (a ∈ n ∧ b ∈ n) ↔ ∃n ∈ Nn ∅ ∈ n)) | 
| 39 | 32, 38 | mpbiri 224 | 
. . . . . 6
⊢ ((a = ∅ ∧ b = ∅) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) | 
| 40 | 24, 27, 39 | syl2anb 465 | 
. . . . 5
⊢ ((℘1a ∈
0c ∧ ℘1b ∈
0c) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) | 
| 41 | 40 | gen2 1547 | 
. . . 4
⊢ ∀a∀b((℘1a ∈
0c ∧ ℘1b ∈
0c) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) | 
| 42 |   | nfv 1619 | 
. . . . . . 7
⊢ Ⅎa k ∈ Nn | 
| 43 |   | nfa1 1788 | 
. . . . . . 7
⊢ Ⅎa∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) | 
| 44 | 42, 43 | nfan 1824 | 
. . . . . 6
⊢ Ⅎa(k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 45 |   | nfv 1619 | 
. . . . . . . 8
⊢ Ⅎb k ∈ Nn | 
| 46 |   | nfa2 1855 | 
. . . . . . . 8
⊢ Ⅎb∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) | 
| 47 | 45, 46 | nfan 1824 | 
. . . . . . 7
⊢ Ⅎb(k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 48 |   | reeanv 2779 | 
. . . . . . . . 9
⊢ (∃c ∈ k ∃d ∈ k (∃x ∈ ∼ c℘1a = (c ∪
{x}) ∧
∃y ∈ ∼ d℘1b = (d ∪
{y})) ↔ (∃c ∈ k ∃x ∈ ∼ c℘1a = (c ∪
{x}) ∧
∃d ∈ k ∃y ∈ ∼ d℘1b = (d ∪
{y}))) | 
| 49 |   | reeanv 2779 | 
. . . . . . . . . 10
⊢ (∃x ∈ ∼ c∃y ∈ ∼ d(℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) ↔ (∃x ∈ ∼ c℘1a = (c ∪
{x}) ∧
∃y ∈ ∼ d℘1b = (d ∪
{y}))) | 
| 50 | 49 | 2rexbii 2642 | 
. . . . . . . . 9
⊢ (∃c ∈ k ∃d ∈ k ∃x ∈ ∼ c∃y ∈ ∼ d(℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) ↔ ∃c ∈ k ∃d ∈ k (∃x ∈ ∼ c℘1a = (c ∪
{x}) ∧
∃y ∈ ∼ d℘1b = (d ∪
{y}))) | 
| 51 |   | elsuc 4414 | 
. . . . . . . . . 10
⊢ (℘1a ∈ (k +c 1c) ↔
∃c ∈ k ∃x ∈ ∼ c℘1a = (c ∪
{x})) | 
| 52 |   | elsuc 4414 | 
. . . . . . . . . 10
⊢ (℘1b ∈ (k +c 1c) ↔
∃d ∈ k ∃y ∈ ∼ d℘1b = (d ∪
{y})) | 
| 53 | 51, 52 | anbi12i 678 | 
. . . . . . . . 9
⊢ ((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) ↔
(∃c
∈ k ∃x ∈ ∼ c℘1a = (c ∪
{x}) ∧
∃d ∈ k ∃y ∈ ∼ d℘1b = (d ∪
{y}))) | 
| 54 | 48, 50, 53 | 3bitr4ri 269 | 
. . . . . . . 8
⊢ ((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) ↔
∃c ∈ k ∃d ∈ k ∃x ∈ ∼ c∃y ∈ ∼ d(℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y}))) | 
| 55 |   | vex 2863 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ e ∈
V | 
| 56 |   | vex 2863 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ f ∈
V | 
| 57 |   | pw1eq 4144 | 
. . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (a = e →
℘1a = ℘1e) | 
| 58 | 57 | eleq1d 2419 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (a = e →
(℘1a ∈ k ↔ ℘1e ∈ k)) | 
| 59 |   | pw1eq 4144 | 
. . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (b = f →
℘1b = ℘1f) | 
| 60 | 59 | eleq1d 2419 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (b = f →
(℘1b ∈ k ↔ ℘1f ∈ k)) | 
| 61 | 58, 60 | bi2anan9 843 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((a = e ∧ b = f) → ((℘1a ∈ k ∧ ℘1b ∈ k) ↔ (℘1e ∈ k ∧ ℘1f ∈ k))) | 
| 62 |   | elequ1 1713 | 
. . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (a = e →
(a ∈
n ↔ e ∈ n)) | 
| 63 |   | elequ1 1713 | 
. . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (b = f →
(b ∈
n ↔ f ∈ n)) | 
| 64 | 62, 63 | bi2anan9 843 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ ((a = e ∧ b = f) → ((a
∈ n ∧ b ∈ n) ↔
(e ∈
n ∧
f ∈
n))) | 
| 65 | 64 | rexbidv 2636 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((a = e ∧ b = f) → (∃n ∈ Nn (a ∈ n ∧ b ∈ n) ↔ ∃n ∈ Nn (e ∈ n ∧ f ∈ n))) | 
| 66 | 61, 65 | imbi12d 311 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ((a = e ∧ b = f) → (((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1e ∈ k ∧ ℘1f ∈ k) → ∃n ∈ Nn (e ∈ n ∧ f ∈ n)))) | 
| 67 | 66 | spc2gv 2943 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ ((e ∈ V ∧ f ∈ V) → (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ((℘1e ∈ k ∧ ℘1f ∈ k) → ∃n ∈ Nn (e ∈ n ∧ f ∈ n)))) | 
| 68 | 55, 56, 67 | mp2an 653 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ((℘1e ∈ k ∧ ℘1f ∈ k) → ∃n ∈ Nn (e ∈ n ∧ f ∈ n))) | 
| 69 | 68 | com12 27 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ ((℘1e ∈ k ∧ ℘1f ∈ k) → (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ∃n ∈ Nn (e ∈ n ∧ f ∈ n))) | 
| 70 | 69 | ad2antrl 708 | 
. . . . . . . . . . . . . . . . . . 19
⊢ ((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ∃n ∈ Nn (e ∈ n ∧ f ∈ n))) | 
| 71 |   | peano2 4404 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (n ∈ Nn → (n
+c 1c) ∈
Nn ) | 
| 72 | 71 | ad2antrl 708 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → (n
+c 1c) ∈
Nn ) | 
| 73 |   | simprrl 740 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → e
∈ n) | 
| 74 |   | simprrl 740 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → ¬ z ∈ e) | 
| 75 | 74 | adantr 451 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → ¬ z ∈ e) | 
| 76 |   | vex 2863 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ z ∈
V | 
| 77 | 76 | elsuci 4415 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ((e ∈ n ∧ ¬ z ∈ e) → (e
∪ {z}) ∈ (n
+c 1c)) | 
| 78 | 73, 75, 77 | syl2anc 642 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → (e
∪ {z}) ∈ (n
+c 1c)) | 
| 79 |   | simprrr 741 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → f
∈ n) | 
| 80 |   | simprrr 741 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → ¬ w ∈ f) | 
| 81 | 80 | adantr 451 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → ¬ w ∈ f) | 
| 82 |   | vex 2863 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ w ∈
V | 
| 83 | 82 | elsuci 4415 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ((f ∈ n ∧ ¬ w ∈ f) → (f
∪ {w}) ∈ (n
+c 1c)) | 
| 84 | 79, 81, 83 | syl2anc 642 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → (f
∪ {w}) ∈ (n
+c 1c)) | 
| 85 |   | eleq2 2414 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (m = (n
+c 1c) → ((e ∪ {z})
∈ m
↔ (e ∪ {z}) ∈ (n +c
1c))) | 
| 86 |   | eleq2 2414 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (m = (n
+c 1c) → ((f ∪ {w})
∈ m
↔ (f ∪ {w}) ∈ (n +c
1c))) | 
| 87 | 85, 86 | anbi12d 691 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (m = (n
+c 1c) → (((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m) ↔ ((e ∪ {z})
∈ (n
+c 1c) ∧
(f ∪ {w}) ∈ (n +c
1c)))) | 
| 88 | 87 | rspcev 2956 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (((n +c 1c) ∈ Nn ∧ ((e ∪
{z}) ∈
(n +c
1c) ∧ (f ∪ {w})
∈ (n
+c 1c))) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m)) | 
| 89 | 72, 78, 84, 88 | syl12anc 1180 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
(n ∈
Nn ∧ (e ∈ n ∧ f ∈ n))) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m)) | 
| 90 | 89 | expr 598 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
n ∈ Nn ) → ((e
∈ n ∧ f ∈ n) →
∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m))) | 
| 91 | 90 | rexlimdva 2739 | 
. . . . . . . . . . . . . . . . . . 19
⊢ ((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → (∃n ∈ Nn (e ∈ n ∧ f ∈ n) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m))) | 
| 92 | 70, 91 | syld 40 | 
. . . . . . . . . . . . . . . . . 18
⊢ ((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m))) | 
| 93 | 92 | imp 418 | 
. . . . . . . . . . . . . . . . 17
⊢ (((k ∈ Nn ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) ∧
∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m)) | 
| 94 | 93 | an32s 779 | 
. . . . . . . . . . . . . . . 16
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m)) | 
| 95 |   | eleq1 2413 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (c = ℘1e → (c
∈ k
↔ ℘1e ∈ k)) | 
| 96 | 95 | 3ad2ant2 977 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ ((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) →
(c ∈
k ↔ ℘1e ∈ k)) | 
| 97 |   | eleq1 2413 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (d = ℘1f → (d
∈ k
↔ ℘1f ∈ k)) | 
| 98 | 97 | 3ad2ant2 977 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ ((b = (f ∪
{w}) ∧
d = ℘1f ∧ y = {w}) →
(d ∈
k ↔ ℘1f ∈ k)) | 
| 99 | 96, 98 | bi2anan9 843 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
((c ∈
k ∧
d ∈
k) ↔ (℘1e ∈ k ∧ ℘1f ∈ k))) | 
| 100 |   | compleq 3244 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (c = ℘1e → ∼ c
= ∼ ℘1e) | 
| 101 |   | eleq12 2415 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((x = {z} ∧ ∼ c =
∼ ℘1e) → (x
∈ ∼ c
↔ {z} ∈ ∼ ℘1e)) | 
| 102 | 100, 101 | sylan2 460 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ((x = {z} ∧ c = ℘1e) → (x
∈ ∼ c
↔ {z} ∈ ∼ ℘1e)) | 
| 103 |   | snex 4112 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ {z} ∈
V | 
| 104 | 103 | elcompl 3226 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ({z} ∈ ∼ ℘1e ↔ ¬ {z} ∈ ℘1e) | 
| 105 |   | snelpw1 4147 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ({z} ∈ ℘1e ↔ z ∈ e) | 
| 106 | 104, 105 | xchbinx 301 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ({z} ∈ ∼ ℘1e ↔ ¬ z
∈ e) | 
| 107 | 102, 106 | syl6bb 252 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ ((x = {z} ∧ c = ℘1e) → (x
∈ ∼ c
↔ ¬ z ∈ e)) | 
| 108 | 107 | ancoms 439 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ ((c = ℘1e ∧ x = {z}) →
(x ∈
∼ c ↔ ¬ z ∈ e)) | 
| 109 | 108 | 3adant1 973 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ ((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) →
(x ∈
∼ c ↔ ¬ z ∈ e)) | 
| 110 |   | compleq 3244 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (d = ℘1f → ∼ d
= ∼ ℘1f) | 
| 111 |   | eleq12 2415 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((y = {w} ∧ ∼ d =
∼ ℘1f) → (y
∈ ∼ d
↔ {w} ∈ ∼ ℘1f)) | 
| 112 | 110, 111 | sylan2 460 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ((y = {w} ∧ d = ℘1f) → (y
∈ ∼ d
↔ {w} ∈ ∼ ℘1f)) | 
| 113 |   | snex 4112 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ {w} ∈
V | 
| 114 | 113 | elcompl 3226 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ({w} ∈ ∼ ℘1f ↔ ¬ {w} ∈ ℘1f) | 
| 115 |   | snelpw1 4147 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ({w} ∈ ℘1f ↔ w ∈ f) | 
| 116 | 114, 115 | xchbinx 301 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ({w} ∈ ∼ ℘1f ↔ ¬ w
∈ f) | 
| 117 | 112, 116 | syl6bb 252 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ ((y = {w} ∧ d = ℘1f) → (y
∈ ∼ d
↔ ¬ w ∈ f)) | 
| 118 | 117 | ancoms 439 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ ((d = ℘1f ∧ y = {w}) →
(y ∈
∼ d ↔ ¬ w ∈ f)) | 
| 119 | 118 | 3adant1 973 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ ((b = (f ∪
{w}) ∧
d = ℘1f ∧ y = {w}) →
(y ∈
∼ d ↔ ¬ w ∈ f)) | 
| 120 | 109, 119 | bi2anan9 843 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
((x ∈
∼ c ∧
y ∈ ∼
d) ↔ (¬ z ∈ e ∧ ¬ w ∈ f))) | 
| 121 | 99, 120 | anbi12d 691 | 
. . . . . . . . . . . . . . . . . 18
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
(((c ∈
k ∧
d ∈
k) ∧
(x ∈
∼ c ∧
y ∈ ∼
d)) ↔ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f)))) | 
| 122 | 121 | anbi2d 684 | 
. . . . . . . . . . . . . . . . 17
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
(((k ∈
Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) ↔ ((k
∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))))) | 
| 123 |   | eleq1 2413 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (a = (e ∪
{z}) → (a ∈ m ↔ (e
∪ {z}) ∈ m)) | 
| 124 | 123 | 3ad2ant1 976 | 
. . . . . . . . . . . . . . . . . . 19
⊢ ((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) →
(a ∈
m ↔ (e ∪ {z})
∈ m)) | 
| 125 |   | eleq1 2413 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (b = (f ∪
{w}) → (b ∈ m ↔ (f
∪ {w}) ∈ m)) | 
| 126 | 125 | 3ad2ant1 976 | 
. . . . . . . . . . . . . . . . . . 19
⊢ ((b = (f ∪
{w}) ∧
d = ℘1f ∧ y = {w}) →
(b ∈
m ↔ (f ∪ {w})
∈ m)) | 
| 127 | 124, 126 | bi2anan9 843 | 
. . . . . . . . . . . . . . . . . 18
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
((a ∈
m ∧
b ∈
m) ↔ ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m))) | 
| 128 | 127 | rexbidv 2636 | 
. . . . . . . . . . . . . . . . 17
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
(∃m
∈ Nn (a ∈ m ∧ b ∈ m) ↔ ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m))) | 
| 129 | 122, 128 | imbi12d 311 | 
. . . . . . . . . . . . . . . 16
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
((((k ∈
Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → ∃m ∈ Nn (a ∈ m ∧ b ∈ m)) ↔ (((k
∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((℘1e ∈ k ∧ ℘1f ∈ k) ∧ (¬
z ∈
e ∧ ¬
w ∈
f))) → ∃m ∈ Nn ((e ∪ {z})
∈ m ∧ (f ∪
{w}) ∈
m)))) | 
| 130 | 94, 129 | mpbiri 224 | 
. . . . . . . . . . . . . . 15
⊢ (((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
(((k ∈
Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → ∃m ∈ Nn (a ∈ m ∧ b ∈ m))) | 
| 131 | 130 | com12 27 | 
. . . . . . . . . . . . . 14
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → (((a
= (e ∪ {z}) ∧ c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
∃m ∈ Nn (a ∈ m ∧ b ∈ m))) | 
| 132 | 131 | exlimdvv 1637 | 
. . . . . . . . . . . . 13
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → (∃z∃w((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
∃m ∈ Nn (a ∈ m ∧ b ∈ m))) | 
| 133 | 132 | exlimdvv 1637 | 
. . . . . . . . . . . 12
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → (∃e∃f∃z∃w((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) →
∃m ∈ Nn (a ∈ m ∧ b ∈ m))) | 
| 134 |   | eeanv 1913 | 
. . . . . . . . . . . . 13
⊢ (∃e∃f(∃z(a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ ∃w(b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) ↔
(∃e∃z(a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ ∃f∃w(b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w}))) | 
| 135 |   | eeanv 1913 | 
. . . . . . . . . . . . . 14
⊢ (∃z∃w((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) ↔
(∃z(a = (e ∪ {z})
∧ c =
℘1e ∧ x = {z}) ∧ ∃w(b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w}))) | 
| 136 | 135 | 2exbii 1583 | 
. . . . . . . . . . . . 13
⊢ (∃e∃f∃z∃w((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w})) ↔
∃e∃f(∃z(a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ ∃w(b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w}))) | 
| 137 |   | vex 2863 | 
. . . . . . . . . . . . . . 15
⊢ c ∈
V | 
| 138 |   | vex 2863 | 
. . . . . . . . . . . . . . 15
⊢ x ∈
V | 
| 139 | 137, 138 | pw1eqadj 4333 | 
. . . . . . . . . . . . . 14
⊢ (℘1a = (c ∪
{x}) ↔ ∃e∃z(a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z})) | 
| 140 |   | vex 2863 | 
. . . . . . . . . . . . . . 15
⊢ d ∈
V | 
| 141 |   | vex 2863 | 
. . . . . . . . . . . . . . 15
⊢ y ∈
V | 
| 142 | 140, 141 | pw1eqadj 4333 | 
. . . . . . . . . . . . . 14
⊢ (℘1b = (d ∪
{y}) ↔ ∃f∃w(b = (f ∪
{w}) ∧
d = ℘1f ∧ y = {w})) | 
| 143 | 139, 142 | anbi12i 678 | 
. . . . . . . . . . . . 13
⊢ ((℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) ↔ (∃e∃z(a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ ∃f∃w(b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w}))) | 
| 144 | 134, 136,
143 | 3bitr4ri 269 | 
. . . . . . . . . . . 12
⊢ ((℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) ↔ ∃e∃f∃z∃w((a = (e ∪
{z}) ∧
c = ℘1e ∧ x = {z}) ∧ (b = (f ∪ {w})
∧ d =
℘1f ∧ y = {w}))) | 
| 145 |   | elequ2 1715 | 
. . . . . . . . . . . . . 14
⊢ (n = m →
(a ∈
n ↔ a ∈ m)) | 
| 146 |   | elequ2 1715 | 
. . . . . . . . . . . . . 14
⊢ (n = m →
(b ∈
n ↔ b ∈ m)) | 
| 147 | 145, 146 | anbi12d 691 | 
. . . . . . . . . . . . 13
⊢ (n = m →
((a ∈
n ∧
b ∈
n) ↔ (a ∈ m ∧ b ∈ m))) | 
| 148 | 147 | cbvrexv 2837 | 
. . . . . . . . . . . 12
⊢ (∃n ∈ Nn (a ∈ n ∧ b ∈ n) ↔ ∃m ∈ Nn (a ∈ m ∧ b ∈ m)) | 
| 149 | 133, 144,
148 | 3imtr4g 261 | 
. . . . . . . . . . 11
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ ((c ∈ k ∧ d ∈ k) ∧ (x ∈ ∼ c ∧ y ∈ ∼ d))) → ((℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 150 | 149 | expr 598 | 
. . . . . . . . . 10
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ (c ∈ k ∧ d ∈ k)) → ((x
∈ ∼ c
∧ y ∈ ∼ d)
→ ((℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 151 | 150 | rexlimdvv 2745 | 
. . . . . . . . 9
⊢ (((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) ∧ (c ∈ k ∧ d ∈ k)) → (∃x ∈ ∼ c∃y ∈ ∼ d(℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 152 | 151 | rexlimdvva 2746 | 
. . . . . . . 8
⊢ ((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) → (∃c ∈ k ∃d ∈ k ∃x ∈ ∼ c∃y ∈ ∼ d(℘1a = (c ∪
{x}) ∧
℘1b = (d ∪
{y})) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 153 | 54, 152 | syl5bi 208 | 
. . . . . . 7
⊢ ((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) → ((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 154 | 47, 153 | alrimi 1765 | 
. . . . . 6
⊢ ((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) → ∀b((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 155 | 44, 154 | alrimi 1765 | 
. . . . 5
⊢ ((k ∈ Nn ∧ ∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) → ∀a∀b((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 156 | 155 | ex 423 | 
. . . 4
⊢ (k ∈ Nn → (∀a∀b((℘1a ∈ k ∧ ℘1b ∈ k) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ∀a∀b((℘1a ∈ (k +c 1c) ∧ ℘1b ∈ (k +c 1c)) →
∃n ∈ Nn (a ∈ n ∧ b ∈ n)))) | 
| 157 | 1, 6, 11, 16, 21, 41, 156 | finds 4412 | 
. . 3
⊢ (M ∈ Nn → ∀a∀b((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n))) | 
| 158 |   | elex 2868 | 
. . . . . 6
⊢ (℘1A ∈ M → ℘1A ∈
V) | 
| 159 |   | pw1exb 4327 | 
. . . . . 6
⊢ (℘1A ∈ V ↔
A ∈
V) | 
| 160 | 158, 159 | sylib 188 | 
. . . . 5
⊢ (℘1A ∈ M → A ∈ V) | 
| 161 |   | elex 2868 | 
. . . . . 6
⊢ (℘1B ∈ M → ℘1B ∈
V) | 
| 162 |   | pw1exb 4327 | 
. . . . . 6
⊢ (℘1B ∈ V ↔
B ∈
V) | 
| 163 | 161, 162 | sylib 188 | 
. . . . 5
⊢ (℘1B ∈ M → B ∈ V) | 
| 164 |   | pw1eq 4144 | 
. . . . . . . . 9
⊢ (a = A →
℘1a = ℘1A) | 
| 165 | 164 | eleq1d 2419 | 
. . . . . . . 8
⊢ (a = A →
(℘1a ∈ M ↔ ℘1A ∈ M)) | 
| 166 |   | pw1eq 4144 | 
. . . . . . . . 9
⊢ (b = B →
℘1b = ℘1B) | 
| 167 | 166 | eleq1d 2419 | 
. . . . . . . 8
⊢ (b = B →
(℘1b ∈ M ↔ ℘1B ∈ M)) | 
| 168 | 165, 167 | bi2anan9 843 | 
. . . . . . 7
⊢ ((a = A ∧ b = B) → ((℘1a ∈ M ∧ ℘1b ∈ M) ↔ (℘1A ∈ M ∧ ℘1B ∈ M))) | 
| 169 |   | eleq1 2413 | 
. . . . . . . . 9
⊢ (a = A →
(a ∈
n ↔ A ∈ n)) | 
| 170 |   | eleq1 2413 | 
. . . . . . . . 9
⊢ (b = B →
(b ∈
n ↔ B ∈ n)) | 
| 171 | 169, 170 | bi2anan9 843 | 
. . . . . . . 8
⊢ ((a = A ∧ b = B) → ((a
∈ n ∧ b ∈ n) ↔
(A ∈
n ∧
B ∈
n))) | 
| 172 | 171 | rexbidv 2636 | 
. . . . . . 7
⊢ ((a = A ∧ b = B) → (∃n ∈ Nn (a ∈ n ∧ b ∈ n) ↔ ∃n ∈ Nn (A ∈ n ∧ B ∈ n))) | 
| 173 | 168, 172 | imbi12d 311 | 
. . . . . 6
⊢ ((a = A ∧ b = B) → (((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) ↔ ((℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n)))) | 
| 174 | 173 | spc2gv 2943 | 
. . . . 5
⊢ ((A ∈ V ∧ B ∈ V) → (∀a∀b((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ((℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n)))) | 
| 175 | 160, 163,
174 | syl2an 463 | 
. . . 4
⊢ ((℘1A ∈ M ∧ ℘1B ∈ M) → (∀a∀b((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ((℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n)))) | 
| 176 | 175 | pm2.43b 46 | 
. . 3
⊢ (∀a∀b((℘1a ∈ M ∧ ℘1b ∈ M) → ∃n ∈ Nn (a ∈ n ∧ b ∈ n)) → ((℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n))) | 
| 177 | 157, 176 | syl 15 | 
. 2
⊢ (M ∈ Nn → ((℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n))) | 
| 178 | 177 | 3impib 1149 | 
1
⊢ ((M ∈ Nn ∧ ℘1A ∈ M ∧ ℘1B ∈ M) → ∃n ∈ Nn (A ∈ n ∧ B ∈ n)) |