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Mirrors > Home > MPE Home > Th. List > fvres | Structured version Visualization version GIF version |
Description: The value of a restricted function. (Contributed by NM, 2-Aug-1994.) |
Ref | Expression |
---|---|
fvres | ⊢ (𝐴 ∈ 𝐵 → ((𝐹 ↾ 𝐵)‘𝐴) = (𝐹‘𝐴)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vex 3426 | . . . . 5 ⊢ 𝑥 ∈ V | |
2 | 1 | brresi 5889 | . . . 4 ⊢ (𝐴(𝐹 ↾ 𝐵)𝑥 ↔ (𝐴 ∈ 𝐵 ∧ 𝐴𝐹𝑥)) |
3 | 2 | baib 535 | . . 3 ⊢ (𝐴 ∈ 𝐵 → (𝐴(𝐹 ↾ 𝐵)𝑥 ↔ 𝐴𝐹𝑥)) |
4 | 3 | iotabidv 6402 | . 2 ⊢ (𝐴 ∈ 𝐵 → (℩𝑥𝐴(𝐹 ↾ 𝐵)𝑥) = (℩𝑥𝐴𝐹𝑥)) |
5 | df-fv 6426 | . 2 ⊢ ((𝐹 ↾ 𝐵)‘𝐴) = (℩𝑥𝐴(𝐹 ↾ 𝐵)𝑥) | |
6 | df-fv 6426 | . 2 ⊢ (𝐹‘𝐴) = (℩𝑥𝐴𝐹𝑥) | |
7 | 4, 5, 6 | 3eqtr4g 2804 | 1 ⊢ (𝐴 ∈ 𝐵 → ((𝐹 ↾ 𝐵)‘𝐴) = (𝐹‘𝐴)) |
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