| Step | Hyp | Ref
| Expression |
| 1 | | ralnex 2992 |
. . . . 5
⊢
(∀𝑧 ∈
{𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ¬ ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑) |
| 2 | | vex 3203 |
. . . . . . . 8
⊢ 𝑧 ∈ V |
| 3 | | sbcng 3476 |
. . . . . . . 8
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑)) |
| 4 | 2, 3 | ax-mp 5 |
. . . . . . 7
⊢
([𝑧 / 𝑥] ¬ 𝜑 ↔ ¬ [𝑧 / 𝑥]𝜑) |
| 5 | 4 | bicomi 214 |
. . . . . 6
⊢ (¬
[𝑧 / 𝑥]𝜑 ↔ [𝑧 / 𝑥] ¬ 𝜑) |
| 6 | 5 | ralbii 2980 |
. . . . 5
⊢
(∀𝑧 ∈
{𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ [𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑) |
| 7 | 1, 6 | bitr3i 266 |
. . . 4
⊢ (¬
∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑 ↔ ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥] ¬ 𝜑) |
| 8 | | df-rab 2921 |
. . . . . . 7
⊢ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)} |
| 9 | 8 | eleq2i 2693 |
. . . . . 6
⊢ (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ 𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)}) |
| 10 | | df-sbc 3436 |
. . . . . . 7
⊢
([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ 𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)}) |
| 11 | | sbcan 3478 |
. . . . . . . 8
⊢
([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ ([𝑧 / 𝑥]𝑥 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑)) |
| 12 | | sbcel1v 3495 |
. . . . . . . . 9
⊢
([𝑧 / 𝑥]𝑥 ∈ 𝐴 ↔ 𝑧 ∈ 𝐴) |
| 13 | 12 | anbi1i 731 |
. . . . . . . 8
⊢
(([𝑧 / 𝑥]𝑥 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑) ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑)) |
| 14 | 11, 13 | bitri 264 |
. . . . . . 7
⊢
([𝑧 / 𝑥](𝑥 ∈ 𝐴 ∧ ¬ 𝜑) ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑)) |
| 15 | 10, 14 | bitr3i 266 |
. . . . . 6
⊢ (𝑧 ∈ {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ ¬ 𝜑)} ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑)) |
| 16 | 9, 15 | bitri 264 |
. . . . 5
⊢ (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ↔ (𝑧 ∈ 𝐴 ∧ [𝑧 / 𝑥] ¬ 𝜑)) |
| 17 | 16 | simprbi 480 |
. . . 4
⊢ (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → [𝑧 / 𝑥] ¬ 𝜑) |
| 18 | 7, 17 | mprgbir 2927 |
. . 3
⊢ ¬
∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑 |
| 19 | | bnj110.1 |
. . . . . . . . 9
⊢ 𝐴 ∈ V |
| 20 | 19 | rabex 4813 |
. . . . . . . 8
⊢ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V |
| 21 | 20 | biantrur 527 |
. . . . . . 7
⊢ (𝑅 Fr 𝐴 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴)) |
| 22 | | rexnal 2995 |
. . . . . . . 8
⊢
(∃𝑥 ∈
𝐴 ¬ 𝜑 ↔ ¬ ∀𝑥 ∈ 𝐴 𝜑) |
| 23 | | rabn0 3958 |
. . . . . . . . 9
⊢ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ∃𝑥 ∈ 𝐴 ¬ 𝜑) |
| 24 | | ssrab2 3687 |
. . . . . . . . . 10
⊢ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 |
| 25 | 24 | biantrur 527 |
. . . . . . . . 9
⊢ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅ ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)) |
| 26 | 23, 25 | bitr3i 266 |
. . . . . . . 8
⊢
(∃𝑥 ∈
𝐴 ¬ 𝜑 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)) |
| 27 | 22, 26 | bitr3i 266 |
. . . . . . 7
⊢ (¬
∀𝑥 ∈ 𝐴 𝜑 ↔ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)) |
| 28 | | fri 5076 |
. . . . . . 7
⊢ ((({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ∈ V ∧ 𝑅 Fr 𝐴) ∧ ({𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ⊆ 𝐴 ∧ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ≠ ∅)) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧) |
| 29 | 21, 27, 28 | syl2anb 496 |
. . . . . 6
⊢ ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}∀𝑤 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧) |
| 30 | | eqid 2622 |
. . . . . . . 8
⊢ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} = {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} |
| 31 | 30 | bnj23 30784 |
. . . . . . 7
⊢
(∀𝑤 ∈
{𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧 → ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)) |
| 32 | | df-ral 2917 |
. . . . . . . . . 10
⊢
(∀𝑦 ∈
𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))) |
| 33 | 32 | sbcbii 3491 |
. . . . . . . . 9
⊢
([𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ [𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))) |
| 34 | | sbcal 3485 |
. . . . . . . . . 10
⊢
([𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦[𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))) |
| 35 | | sbcimg 3477 |
. . . . . . . . . . . . 13
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)))) |
| 36 | 2, 35 | ax-mp 5 |
. . . . . . . . . . . 12
⊢
([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ([𝑧 / 𝑥]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑))) |
| 37 | | nfv 1843 |
. . . . . . . . . . . . . . 15
⊢
Ⅎ𝑥 𝑦 ∈ 𝐴 |
| 38 | 37 | sbcgf 3501 |
. . . . . . . . . . . . . 14
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥]𝑦 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴)) |
| 39 | 2, 38 | ax-mp 5 |
. . . . . . . . . . . . 13
⊢
([𝑧 / 𝑥]𝑦 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴) |
| 40 | | sbcimg 3477 |
. . . . . . . . . . . . . . 15
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥 → [𝑧 / 𝑥][𝑦 / 𝑥]𝜑))) |
| 41 | 2, 40 | ax-mp 5 |
. . . . . . . . . . . . . 14
⊢
([𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ([𝑧 / 𝑥]𝑦𝑅𝑥 → [𝑧 / 𝑥][𝑦 / 𝑥]𝜑)) |
| 42 | | sbcbr2g 4710 |
. . . . . . . . . . . . . . . . 17
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅⦋𝑧 / 𝑥⦌𝑥)) |
| 43 | 2, 42 | ax-mp 5 |
. . . . . . . . . . . . . . . 16
⊢
([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅⦋𝑧 / 𝑥⦌𝑥) |
| 44 | | csbvarg 4003 |
. . . . . . . . . . . . . . . . . 18
⊢ (𝑧 ∈ V →
⦋𝑧 / 𝑥⦌𝑥 = 𝑧) |
| 45 | 2, 44 | ax-mp 5 |
. . . . . . . . . . . . . . . . 17
⊢
⦋𝑧 /
𝑥⦌𝑥 = 𝑧 |
| 46 | 45 | breq2i 4661 |
. . . . . . . . . . . . . . . 16
⊢ (𝑦𝑅⦋𝑧 / 𝑥⦌𝑥 ↔ 𝑦𝑅𝑧) |
| 47 | 43, 46 | bitri 264 |
. . . . . . . . . . . . . . 15
⊢
([𝑧 / 𝑥]𝑦𝑅𝑥 ↔ 𝑦𝑅𝑧) |
| 48 | | nfsbc1v 3455 |
. . . . . . . . . . . . . . . . 17
⊢
Ⅎ𝑥[𝑦 / 𝑥]𝜑 |
| 49 | 48 | sbcgf 3501 |
. . . . . . . . . . . . . . . 16
⊢ (𝑧 ∈ V → ([𝑧 / 𝑥][𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜑)) |
| 50 | 2, 49 | ax-mp 5 |
. . . . . . . . . . . . . . 15
⊢
([𝑧 / 𝑥][𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜑) |
| 51 | 47, 50 | imbi12i 340 |
. . . . . . . . . . . . . 14
⊢
(([𝑧 / 𝑥]𝑦𝑅𝑥 → [𝑧 / 𝑥][𝑦 / 𝑥]𝜑) ↔ (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)) |
| 52 | 41, 51 | bitri 264 |
. . . . . . . . . . . . 13
⊢
([𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)) |
| 53 | 39, 52 | imbi12i 340 |
. . . . . . . . . . . 12
⊢
(([𝑧 / 𝑥]𝑦 ∈ 𝐴 → [𝑧 / 𝑥](𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ (𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 54 | 36, 53 | bitri 264 |
. . . . . . . . . . 11
⊢
([𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ (𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 55 | 54 | albii 1747 |
. . . . . . . . . 10
⊢
(∀𝑦[𝑧 / 𝑥](𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 56 | 34, 55 | bitri 264 |
. . . . . . . . 9
⊢
([𝑧 / 𝑥]∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 57 | 33, 56 | bitri 264 |
. . . . . . . 8
⊢
([𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 58 | | bnj110.2 |
. . . . . . . . 9
⊢ (𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) |
| 59 | 58 | sbcbii 3491 |
. . . . . . . 8
⊢
([𝑧 / 𝑥]𝜓 ↔ [𝑧 / 𝑥]∀𝑦 ∈ 𝐴 (𝑦𝑅𝑥 → [𝑦 / 𝑥]𝜑)) |
| 60 | | df-ral 2917 |
. . . . . . . 8
⊢
(∀𝑦 ∈
𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑) ↔ ∀𝑦(𝑦 ∈ 𝐴 → (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑))) |
| 61 | 57, 59, 60 | 3bitr4i 292 |
. . . . . . 7
⊢
([𝑧 / 𝑥]𝜓 ↔ ∀𝑦 ∈ 𝐴 (𝑦𝑅𝑧 → [𝑦 / 𝑥]𝜑)) |
| 62 | 31, 61 | sylibr 224 |
. . . . . 6
⊢
(∀𝑤 ∈
{𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ¬ 𝑤𝑅𝑧 → [𝑧 / 𝑥]𝜓) |
| 63 | 29, 62 | bnj31 30785 |
. . . . 5
⊢ ((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓) |
| 64 | | nfv 1843 |
. . . . . . . 8
⊢
Ⅎ𝑧(𝜓 → 𝜑) |
| 65 | | nfsbc1v 3455 |
. . . . . . . . 9
⊢
Ⅎ𝑥[𝑧 / 𝑥]𝜓 |
| 66 | | nfsbc1v 3455 |
. . . . . . . . 9
⊢
Ⅎ𝑥[𝑧 / 𝑥]𝜑 |
| 67 | 65, 66 | nfim 1825 |
. . . . . . . 8
⊢
Ⅎ𝑥([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑) |
| 68 | | sbceq1a 3446 |
. . . . . . . . 9
⊢ (𝑥 = 𝑧 → (𝜓 ↔ [𝑧 / 𝑥]𝜓)) |
| 69 | | sbceq1a 3446 |
. . . . . . . . 9
⊢ (𝑥 = 𝑧 → (𝜑 ↔ [𝑧 / 𝑥]𝜑)) |
| 70 | 68, 69 | imbi12d 334 |
. . . . . . . 8
⊢ (𝑥 = 𝑧 → ((𝜓 → 𝜑) ↔ ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑))) |
| 71 | 64, 67, 70 | cbvral 3167 |
. . . . . . 7
⊢
(∀𝑥 ∈
𝐴 (𝜓 → 𝜑) ↔ ∀𝑧 ∈ 𝐴 ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)) |
| 72 | | elrabi 3359 |
. . . . . . . . 9
⊢ (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → 𝑧 ∈ 𝐴) |
| 73 | 72 | imim1i 63 |
. . . . . . . 8
⊢ ((𝑧 ∈ 𝐴 → ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)) → (𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} → ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑))) |
| 74 | 73 | ralimi2 2949 |
. . . . . . 7
⊢
(∀𝑧 ∈
𝐴 ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑) → ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)) |
| 75 | 71, 74 | sylbi 207 |
. . . . . 6
⊢
(∀𝑥 ∈
𝐴 (𝜓 → 𝜑) → ∀𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑)) |
| 76 | | rexim 3008 |
. . . . . 6
⊢
(∀𝑧 ∈
{𝑥 ∈ 𝐴 ∣ ¬ 𝜑} ([𝑧 / 𝑥]𝜓 → [𝑧 / 𝑥]𝜑) → (∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)) |
| 77 | 75, 76 | syl 17 |
. . . . 5
⊢
(∀𝑥 ∈
𝐴 (𝜓 → 𝜑) → (∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜓 → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑)) |
| 78 | 63, 77 | mpan9 486 |
. . . 4
⊢ (((𝑅 Fr 𝐴 ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑) |
| 79 | 78 | an32s 846 |
. . 3
⊢ (((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑧 ∈ {𝑥 ∈ 𝐴 ∣ ¬ 𝜑}[𝑧 / 𝑥]𝜑) |
| 80 | 18, 79 | mto 188 |
. 2
⊢ ¬
((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑) |
| 81 | | iman 440 |
. 2
⊢ (((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 𝜑) ↔ ¬ ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) ∧ ¬ ∀𝑥 ∈ 𝐴 𝜑)) |
| 82 | 80, 81 | mpbir 221 |
1
⊢ ((𝑅 Fr 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 → 𝜑)) → ∀𝑥 ∈ 𝐴 𝜑) |