| Step | Hyp | Ref
| Expression |
| 1 | | rexeq 2694 |
. . 3
⊢ (𝑤 = ∅ → (∃𝑥 ∈ 𝑤 𝜑 ↔ ∃𝑥 ∈ ∅ 𝜑)) |
| 2 | 1 | dcbid 839 |
. 2
⊢ (𝑤 = ∅ →
(DECID ∃𝑥 ∈ 𝑤 𝜑 ↔ DECID ∃𝑥 ∈ ∅ 𝜑)) |
| 3 | | rexeq 2694 |
. . 3
⊢ (𝑤 = 𝑦 → (∃𝑥 ∈ 𝑤 𝜑 ↔ ∃𝑥 ∈ 𝑦 𝜑)) |
| 4 | 3 | dcbid 839 |
. 2
⊢ (𝑤 = 𝑦 → (DECID ∃𝑥 ∈ 𝑤 𝜑 ↔ DECID ∃𝑥 ∈ 𝑦 𝜑)) |
| 5 | | rexeq 2694 |
. . 3
⊢ (𝑤 = (𝑦 ∪ {𝑧}) → (∃𝑥 ∈ 𝑤 𝜑 ↔ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 6 | 5 | dcbid 839 |
. 2
⊢ (𝑤 = (𝑦 ∪ {𝑧}) → (DECID ∃𝑥 ∈ 𝑤 𝜑 ↔ DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 7 | | rexeq 2694 |
. . 3
⊢ (𝑤 = 𝐴 → (∃𝑥 ∈ 𝑤 𝜑 ↔ ∃𝑥 ∈ 𝐴 𝜑)) |
| 8 | 7 | dcbid 839 |
. 2
⊢ (𝑤 = 𝐴 → (DECID ∃𝑥 ∈ 𝑤 𝜑 ↔ DECID ∃𝑥 ∈ 𝐴 𝜑)) |
| 9 | | rex0 3469 |
. . . . 5
⊢ ¬
∃𝑥 ∈ ∅
𝜑 |
| 10 | 9 | olci 733 |
. . . 4
⊢
(∃𝑥 ∈
∅ 𝜑 ∨ ¬
∃𝑥 ∈ ∅
𝜑) |
| 11 | | df-dc 836 |
. . . 4
⊢
(DECID ∃𝑥 ∈ ∅ 𝜑 ↔ (∃𝑥 ∈ ∅ 𝜑 ∨ ¬ ∃𝑥 ∈ ∅ 𝜑)) |
| 12 | 10, 11 | mpbir 146 |
. . 3
⊢
DECID ∃𝑥 ∈ ∅ 𝜑 |
| 13 | 12 | a1i 9 |
. 2
⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 DECID 𝜑) → DECID ∃𝑥 ∈ ∅ 𝜑) |
| 14 | | simpr 110 |
. . . . . . . . 9
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → [𝑧 / 𝑥]𝜑) |
| 15 | | sbsbc 2993 |
. . . . . . . . . 10
⊢ ([𝑧 / 𝑥]𝜑 ↔ [𝑧 / 𝑥]𝜑) |
| 16 | | rexsns 3662 |
. . . . . . . . . 10
⊢
(∃𝑥 ∈
{𝑧}𝜑 ↔ [𝑧 / 𝑥]𝜑) |
| 17 | 15, 16 | bitr4i 187 |
. . . . . . . . 9
⊢ ([𝑧 / 𝑥]𝜑 ↔ ∃𝑥 ∈ {𝑧}𝜑) |
| 18 | 14, 17 | sylib 122 |
. . . . . . . 8
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → ∃𝑥 ∈ {𝑧}𝜑) |
| 19 | 18 | olcd 735 |
. . . . . . 7
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → (∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑)) |
| 20 | | rexun 3344 |
. . . . . . 7
⊢
(∃𝑥 ∈
(𝑦 ∪ {𝑧})𝜑 ↔ (∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑)) |
| 21 | 19, 20 | sylibr 134 |
. . . . . 6
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 22 | 21 | orcd 734 |
. . . . 5
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → (∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ∨ ¬ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 23 | | df-dc 836 |
. . . . 5
⊢
(DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ↔ (∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ∨ ¬ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 24 | 22, 23 | sylibr 134 |
. . . 4
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ [𝑧 / 𝑥]𝜑) → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 25 | | simpr 110 |
. . . . . . . . 9
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ∃𝑥 ∈ 𝑦 𝜑) → ∃𝑥 ∈ 𝑦 𝜑) |
| 26 | 25 | orcd 734 |
. . . . . . . 8
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ∃𝑥 ∈ 𝑦 𝜑) → (∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑)) |
| 27 | 26, 20 | sylibr 134 |
. . . . . . 7
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ∃𝑥 ∈ 𝑦 𝜑) → ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 28 | 27 | orcd 734 |
. . . . . 6
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ∃𝑥 ∈ 𝑦 𝜑) → (∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ∨ ¬ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 29 | 28, 23 | sylibr 134 |
. . . . 5
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ∃𝑥 ∈ 𝑦 𝜑) → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 30 | | simpr 110 |
. . . . . . . . 9
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → ¬ ∃𝑥 ∈ 𝑦 𝜑) |
| 31 | | simpr 110 |
. . . . . . . . . . 11
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) → ¬ [𝑧 / 𝑥]𝜑) |
| 32 | 17 | notbii 669 |
. . . . . . . . . . 11
⊢ (¬
[𝑧 / 𝑥]𝜑 ↔ ¬ ∃𝑥 ∈ {𝑧}𝜑) |
| 33 | 31, 32 | sylib 122 |
. . . . . . . . . 10
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) → ¬ ∃𝑥 ∈ {𝑧}𝜑) |
| 34 | 33 | adantr 276 |
. . . . . . . . 9
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → ¬ ∃𝑥 ∈ {𝑧}𝜑) |
| 35 | | ioran 753 |
. . . . . . . . 9
⊢ (¬
(∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑) ↔ (¬ ∃𝑥 ∈ 𝑦 𝜑 ∧ ¬ ∃𝑥 ∈ {𝑧}𝜑)) |
| 36 | 30, 34, 35 | sylanbrc 417 |
. . . . . . . 8
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → ¬ (∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑)) |
| 37 | 20 | notbii 669 |
. . . . . . . 8
⊢ (¬
∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ↔ ¬ (∃𝑥 ∈ 𝑦 𝜑 ∨ ∃𝑥 ∈ {𝑧}𝜑)) |
| 38 | 36, 37 | sylibr 134 |
. . . . . . 7
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → ¬ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 39 | 38 | olcd 735 |
. . . . . 6
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → (∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑 ∨ ¬ ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 40 | 39, 23 | sylibr 134 |
. . . . 5
⊢
(((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) ∧ ¬ ∃𝑥 ∈ 𝑦 𝜑) → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 41 | | exmiddc 837 |
. . . . . 6
⊢
(DECID ∃𝑥 ∈ 𝑦 𝜑 → (∃𝑥 ∈ 𝑦 𝜑 ∨ ¬ ∃𝑥 ∈ 𝑦 𝜑)) |
| 42 | 41 | ad2antlr 489 |
. . . . 5
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) → (∃𝑥 ∈ 𝑦 𝜑 ∨ ¬ ∃𝑥 ∈ 𝑦 𝜑)) |
| 43 | 29, 40, 42 | mpjaodan 799 |
. . . 4
⊢
((((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) ∧ ¬ [𝑧 / 𝑥]𝜑) → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 44 | | simplrr 536 |
. . . . . . 7
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → 𝑧 ∈ (𝐴 ∖ 𝑦)) |
| 45 | 44 | eldifad 3168 |
. . . . . 6
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → 𝑧 ∈ 𝐴) |
| 46 | | simp-4r 542 |
. . . . . 6
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → ∀𝑥 ∈ 𝐴 DECID 𝜑) |
| 47 | | nfs1v 1958 |
. . . . . . . 8
⊢
Ⅎ𝑥[𝑧 / 𝑥]𝜑 |
| 48 | 47 | nfdc 1673 |
. . . . . . 7
⊢
Ⅎ𝑥DECID [𝑧 / 𝑥]𝜑 |
| 49 | | sbequ12 1785 |
. . . . . . . 8
⊢ (𝑥 = 𝑧 → (𝜑 ↔ [𝑧 / 𝑥]𝜑)) |
| 50 | 49 | dcbid 839 |
. . . . . . 7
⊢ (𝑥 = 𝑧 → (DECID 𝜑 ↔ DECID [𝑧 / 𝑥]𝜑)) |
| 51 | 48, 50 | rspc 2862 |
. . . . . 6
⊢ (𝑧 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 DECID 𝜑 → DECID [𝑧 / 𝑥]𝜑)) |
| 52 | 45, 46, 51 | sylc 62 |
. . . . 5
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → DECID [𝑧 / 𝑥]𝜑) |
| 53 | | exmiddc 837 |
. . . . 5
⊢
(DECID [𝑧 / 𝑥]𝜑 → ([𝑧 / 𝑥]𝜑 ∨ ¬ [𝑧 / 𝑥]𝜑)) |
| 54 | 52, 53 | syl 14 |
. . . 4
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → ([𝑧 / 𝑥]𝜑 ∨ ¬ [𝑧 / 𝑥]𝜑)) |
| 55 | 24, 43, 54 | mpjaodan 799 |
. . 3
⊢
(((((𝐴 ∈ Fin
∧ ∀𝑥 ∈
𝐴 DECID
𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) ∧ DECID ∃𝑥 ∈ 𝑦 𝜑) → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑) |
| 56 | 55 | ex 115 |
. 2
⊢ ((((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 DECID 𝜑) ∧ 𝑦 ∈ Fin) ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) → (DECID ∃𝑥 ∈ 𝑦 𝜑 → DECID ∃𝑥 ∈ (𝑦 ∪ {𝑧})𝜑)) |
| 57 | | simpl 109 |
. 2
⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 DECID 𝜑) → 𝐴 ∈ Fin) |
| 58 | 2, 4, 6, 8, 13, 56, 57 | findcard2sd 6962 |
1
⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 DECID 𝜑) → DECID ∃𝑥 ∈ 𝐴 𝜑) |