Proof of Theorem fvmptt
| Step | Hyp | Ref
 | Expression | 
| 1 |   | simp2 1000 | 
. . 3
⊢
((∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) ∧ 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵) ∧ (𝐴 ∈ 𝐷 ∧ 𝐶 ∈ 𝑉)) → 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵)) | 
| 2 | 1 | fveq1d 5560 | 
. 2
⊢
((∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) ∧ 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵) ∧ (𝐴 ∈ 𝐷 ∧ 𝐶 ∈ 𝑉)) → (𝐹‘𝐴) = ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴)) | 
| 3 |   | risset 2525 | 
. . . . 5
⊢ (𝐴 ∈ 𝐷 ↔ ∃𝑥 ∈ 𝐷 𝑥 = 𝐴) | 
| 4 |   | elex 2774 | 
. . . . . 6
⊢ (𝐶 ∈ 𝑉 → 𝐶 ∈ V) | 
| 5 |   | nfa1 1555 | 
. . . . . . 7
⊢
Ⅎ𝑥∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) | 
| 6 |   | nfv 1542 | 
. . . . . . . 8
⊢
Ⅎ𝑥 𝐶 ∈ V | 
| 7 |   | nffvmpt1 5569 | 
. . . . . . . . 9
⊢
Ⅎ𝑥((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) | 
| 8 | 7 | nfeq1 2349 | 
. . . . . . . 8
⊢
Ⅎ𝑥((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶 | 
| 9 | 6, 8 | nfim 1586 | 
. . . . . . 7
⊢
Ⅎ𝑥(𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶) | 
| 10 |   | simprl 529 | 
. . . . . . . . . . . . 13
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → 𝑥 ∈ 𝐷) | 
| 11 |   | simplr 528 | 
. . . . . . . . . . . . . 14
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → 𝐵 = 𝐶) | 
| 12 |   | simprr 531 | 
. . . . . . . . . . . . . 14
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → 𝐶 ∈ V) | 
| 13 | 11, 12 | eqeltrd 2273 | 
. . . . . . . . . . . . 13
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → 𝐵 ∈ V) | 
| 14 |   | eqid 2196 | 
. . . . . . . . . . . . . 14
⊢ (𝑥 ∈ 𝐷 ↦ 𝐵) = (𝑥 ∈ 𝐷 ↦ 𝐵) | 
| 15 | 14 | fvmpt2 5645 | 
. . . . . . . . . . . . 13
⊢ ((𝑥 ∈ 𝐷 ∧ 𝐵 ∈ V) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝑥) = 𝐵) | 
| 16 | 10, 13, 15 | syl2anc 411 | 
. . . . . . . . . . . 12
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝑥) = 𝐵) | 
| 17 |   | simpll 527 | 
. . . . . . . . . . . . 13
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → 𝑥 = 𝐴) | 
| 18 | 17 | fveq2d 5562 | 
. . . . . . . . . . . 12
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝑥) = ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴)) | 
| 19 | 16, 18, 11 | 3eqtr3d 2237 | 
. . . . . . . . . . 11
⊢ (((𝑥 = 𝐴 ∧ 𝐵 = 𝐶) ∧ (𝑥 ∈ 𝐷 ∧ 𝐶 ∈ V)) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶) | 
| 20 | 19 | exp43 372 | 
. . . . . . . . . 10
⊢ (𝑥 = 𝐴 → (𝐵 = 𝐶 → (𝑥 ∈ 𝐷 → (𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶)))) | 
| 21 | 20 | a2i 11 | 
. . . . . . . . 9
⊢ ((𝑥 = 𝐴 → 𝐵 = 𝐶) → (𝑥 = 𝐴 → (𝑥 ∈ 𝐷 → (𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶)))) | 
| 22 | 21 | com23 78 | 
. . . . . . . 8
⊢ ((𝑥 = 𝐴 → 𝐵 = 𝐶) → (𝑥 ∈ 𝐷 → (𝑥 = 𝐴 → (𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶)))) | 
| 23 | 22 | sps 1551 | 
. . . . . . 7
⊢
(∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) → (𝑥 ∈ 𝐷 → (𝑥 = 𝐴 → (𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶)))) | 
| 24 | 5, 9, 23 | rexlimd 2611 | 
. . . . . 6
⊢
(∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) → (∃𝑥 ∈ 𝐷 𝑥 = 𝐴 → (𝐶 ∈ V → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶))) | 
| 25 | 4, 24 | syl7 69 | 
. . . . 5
⊢
(∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) → (∃𝑥 ∈ 𝐷 𝑥 = 𝐴 → (𝐶 ∈ 𝑉 → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶))) | 
| 26 | 3, 25 | biimtrid 152 | 
. . . 4
⊢
(∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) → (𝐴 ∈ 𝐷 → (𝐶 ∈ 𝑉 → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶))) | 
| 27 | 26 | imp32 257 | 
. . 3
⊢
((∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) ∧ (𝐴 ∈ 𝐷 ∧ 𝐶 ∈ 𝑉)) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶) | 
| 28 | 27 | 3adant2 1018 | 
. 2
⊢
((∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) ∧ 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵) ∧ (𝐴 ∈ 𝐷 ∧ 𝐶 ∈ 𝑉)) → ((𝑥 ∈ 𝐷 ↦ 𝐵)‘𝐴) = 𝐶) | 
| 29 | 2, 28 | eqtrd 2229 | 
1
⊢
((∀𝑥(𝑥 = 𝐴 → 𝐵 = 𝐶) ∧ 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵) ∧ (𝐴 ∈ 𝐷 ∧ 𝐶 ∈ 𝑉)) → (𝐹‘𝐴) = 𝐶) |