Description: The domain of a function. (Contributed by Glauco Siliprandi, 23-Oct-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | fndmd.1 | ⊢ ( 𝜑 → 𝐹 Fn 𝐴 ) | |
Assertion | fndmd | ⊢ ( 𝜑 → dom 𝐹 = 𝐴 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fndmd.1 | ⊢ ( 𝜑 → 𝐹 Fn 𝐴 ) | |
2 | fndm | ⊢ ( 𝐹 Fn 𝐴 → dom 𝐹 = 𝐴 ) | |
3 | 1 2 | syl | ⊢ ( 𝜑 → dom 𝐹 = 𝐴 ) |