Proof of Theorem findcard2d
| Step | Hyp | Ref
 | Expression | 
| 1 |   | ssid 3203 | 
. 2
⊢ 𝐴 ⊆ 𝐴 | 
| 2 |   | findcard2d.a | 
. . . 4
⊢ (𝜑 → 𝐴 ∈ Fin) | 
| 3 | 2 | adantr 276 | 
. . 3
⊢ ((𝜑 ∧ 𝐴 ⊆ 𝐴) → 𝐴 ∈ Fin) | 
| 4 |   | sseq1 3206 | 
. . . . . 6
⊢ (𝑥 = ∅ → (𝑥 ⊆ 𝐴 ↔ ∅ ⊆ 𝐴)) | 
| 5 | 4 | anbi2d 464 | 
. . . . 5
⊢ (𝑥 = ∅ → ((𝜑 ∧ 𝑥 ⊆ 𝐴) ↔ (𝜑 ∧ ∅ ⊆ 𝐴))) | 
| 6 |   | findcard2d.ch | 
. . . . 5
⊢ (𝑥 = ∅ → (𝜓 ↔ 𝜒)) | 
| 7 | 5, 6 | imbi12d 234 | 
. . . 4
⊢ (𝑥 = ∅ → (((𝜑 ∧ 𝑥 ⊆ 𝐴) → 𝜓) ↔ ((𝜑 ∧ ∅ ⊆ 𝐴) → 𝜒))) | 
| 8 |   | sseq1 3206 | 
. . . . . 6
⊢ (𝑥 = 𝑦 → (𝑥 ⊆ 𝐴 ↔ 𝑦 ⊆ 𝐴)) | 
| 9 | 8 | anbi2d 464 | 
. . . . 5
⊢ (𝑥 = 𝑦 → ((𝜑 ∧ 𝑥 ⊆ 𝐴) ↔ (𝜑 ∧ 𝑦 ⊆ 𝐴))) | 
| 10 |   | findcard2d.th | 
. . . . 5
⊢ (𝑥 = 𝑦 → (𝜓 ↔ 𝜃)) | 
| 11 | 9, 10 | imbi12d 234 | 
. . . 4
⊢ (𝑥 = 𝑦 → (((𝜑 ∧ 𝑥 ⊆ 𝐴) → 𝜓) ↔ ((𝜑 ∧ 𝑦 ⊆ 𝐴) → 𝜃))) | 
| 12 |   | sseq1 3206 | 
. . . . . 6
⊢ (𝑥 = (𝑦 ∪ {𝑧}) → (𝑥 ⊆ 𝐴 ↔ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) | 
| 13 | 12 | anbi2d 464 | 
. . . . 5
⊢ (𝑥 = (𝑦 ∪ {𝑧}) → ((𝜑 ∧ 𝑥 ⊆ 𝐴) ↔ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴))) | 
| 14 |   | findcard2d.ta | 
. . . . 5
⊢ (𝑥 = (𝑦 ∪ {𝑧}) → (𝜓 ↔ 𝜏)) | 
| 15 | 13, 14 | imbi12d 234 | 
. . . 4
⊢ (𝑥 = (𝑦 ∪ {𝑧}) → (((𝜑 ∧ 𝑥 ⊆ 𝐴) → 𝜓) ↔ ((𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴) → 𝜏))) | 
| 16 |   | sseq1 3206 | 
. . . . . 6
⊢ (𝑥 = 𝐴 → (𝑥 ⊆ 𝐴 ↔ 𝐴 ⊆ 𝐴)) | 
| 17 | 16 | anbi2d 464 | 
. . . . 5
⊢ (𝑥 = 𝐴 → ((𝜑 ∧ 𝑥 ⊆ 𝐴) ↔ (𝜑 ∧ 𝐴 ⊆ 𝐴))) | 
| 18 |   | findcard2d.et | 
. . . . 5
⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜂)) | 
| 19 | 17, 18 | imbi12d 234 | 
. . . 4
⊢ (𝑥 = 𝐴 → (((𝜑 ∧ 𝑥 ⊆ 𝐴) → 𝜓) ↔ ((𝜑 ∧ 𝐴 ⊆ 𝐴) → 𝜂))) | 
| 20 |   | findcard2d.z | 
. . . . 5
⊢ (𝜑 → 𝜒) | 
| 21 | 20 | adantr 276 | 
. . . 4
⊢ ((𝜑 ∧ ∅ ⊆ 𝐴) → 𝜒) | 
| 22 |   | simprl 529 | 
. . . . . . . 8
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → 𝜑) | 
| 23 |   | simprr 531 | 
. . . . . . . . 9
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → (𝑦 ∪ {𝑧}) ⊆ 𝐴) | 
| 24 | 23 | unssad 3340 | 
. . . . . . . 8
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → 𝑦 ⊆ 𝐴) | 
| 25 | 22, 24 | jca 306 | 
. . . . . . 7
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → (𝜑 ∧ 𝑦 ⊆ 𝐴)) | 
| 26 |   | id 19 | 
. . . . . . . . . . 11
⊢ ((𝑦 ∪ {𝑧}) ⊆ 𝐴 → (𝑦 ∪ {𝑧}) ⊆ 𝐴) | 
| 27 |   | vsnid 3654 | 
. . . . . . . . . . . 12
⊢ 𝑧 ∈ {𝑧} | 
| 28 |   | elun2 3331 | 
. . . . . . . . . . . 12
⊢ (𝑧 ∈ {𝑧} → 𝑧 ∈ (𝑦 ∪ {𝑧})) | 
| 29 | 27, 28 | mp1i 10 | 
. . . . . . . . . . 11
⊢ ((𝑦 ∪ {𝑧}) ⊆ 𝐴 → 𝑧 ∈ (𝑦 ∪ {𝑧})) | 
| 30 | 26, 29 | sseldd 3184 | 
. . . . . . . . . 10
⊢ ((𝑦 ∪ {𝑧}) ⊆ 𝐴 → 𝑧 ∈ 𝐴) | 
| 31 | 30 | ad2antll 491 | 
. . . . . . . . 9
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → 𝑧 ∈ 𝐴) | 
| 32 |   | simplr 528 | 
. . . . . . . . 9
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → ¬ 𝑧 ∈ 𝑦) | 
| 33 | 31, 32 | eldifd 3167 | 
. . . . . . . 8
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → 𝑧 ∈ (𝐴 ∖ 𝑦)) | 
| 34 |   | findcard2d.i | 
. . . . . . . 8
⊢ ((𝜑 ∧ (𝑦 ⊆ 𝐴 ∧ 𝑧 ∈ (𝐴 ∖ 𝑦))) → (𝜃 → 𝜏)) | 
| 35 | 22, 24, 33, 34 | syl12anc 1247 | 
. . . . . . 7
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → (𝜃 → 𝜏)) | 
| 36 | 25, 35 | embantd 56 | 
. . . . . 6
⊢ (((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) ∧ (𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴)) → (((𝜑 ∧ 𝑦 ⊆ 𝐴) → 𝜃) → 𝜏)) | 
| 37 | 36 | ex 115 | 
. . . . 5
⊢ ((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) → ((𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴) → (((𝜑 ∧ 𝑦 ⊆ 𝐴) → 𝜃) → 𝜏))) | 
| 38 | 37 | com23 78 | 
. . . 4
⊢ ((𝑦 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑦) → (((𝜑 ∧ 𝑦 ⊆ 𝐴) → 𝜃) → ((𝜑 ∧ (𝑦 ∪ {𝑧}) ⊆ 𝐴) → 𝜏))) | 
| 39 | 7, 11, 15, 19, 21, 38 | findcard2s 6951 | 
. . 3
⊢ (𝐴 ∈ Fin → ((𝜑 ∧ 𝐴 ⊆ 𝐴) → 𝜂)) | 
| 40 | 3, 39 | mpcom 36 | 
. 2
⊢ ((𝜑 ∧ 𝐴 ⊆ 𝐴) → 𝜂) | 
| 41 | 1, 40 | mpan2 425 | 
1
⊢ (𝜑 → 𝜂) |