Step | Hyp | Ref
| Expression |
1 | | mapvalg 8518 |
. . 3
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴 ↑m 𝐵) = {𝑔 ∣ 𝑔:𝐵⟶𝐴}) |
2 | 1 | eleq2d 2823 |
. 2
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐶 ∈ (𝐴 ↑m 𝐵) ↔ 𝐶 ∈ {𝑔 ∣ 𝑔:𝐵⟶𝐴})) |
3 | | fex2 7711 |
. . . . 5
⊢ ((𝐶:𝐵⟶𝐴 ∧ 𝐵 ∈ 𝑊 ∧ 𝐴 ∈ 𝑉) → 𝐶 ∈ V) |
4 | 3 | 3com13 1126 |
. . . 4
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ∧ 𝐶:𝐵⟶𝐴) → 𝐶 ∈ V) |
5 | 4 | 3expia 1123 |
. . 3
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐶:𝐵⟶𝐴 → 𝐶 ∈ V)) |
6 | | feq1 6526 |
. . . 4
⊢ (𝑔 = 𝐶 → (𝑔:𝐵⟶𝐴 ↔ 𝐶:𝐵⟶𝐴)) |
7 | 6 | elab3g 3594 |
. . 3
⊢ ((𝐶:𝐵⟶𝐴 → 𝐶 ∈ V) → (𝐶 ∈ {𝑔 ∣ 𝑔:𝐵⟶𝐴} ↔ 𝐶:𝐵⟶𝐴)) |
8 | 5, 7 | syl 17 |
. 2
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐶 ∈ {𝑔 ∣ 𝑔:𝐵⟶𝐴} ↔ 𝐶:𝐵⟶𝐴)) |
9 | 2, 8 | bitrd 282 |
1
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐶 ∈ (𝐴 ↑m 𝐵) ↔ 𝐶:𝐵⟶𝐴)) |