Theorem fdmd 5180

Description: Deduction form of fdm 5179. The domain of a mapping. (Contributed by Glauco Siliprandi, 26-Jun-2021.)

Hypothesis

Ref	Expression
fdmd.1	⊢ (𝜑 → 𝐹:𝐴⟶𝐵)

Assertion

Ref	Expression
fdmd	⊢ (𝜑 → dom 𝐹 = 𝐴)

Proof of Theorem fdmd

Step	Hyp	Ref	Expression
1		fdmd.1	. 2 ⊢ (𝜑 → 𝐹:𝐴⟶𝐵)
2		fdm 5179	. 2 ⊢ (𝐹:𝐴⟶𝐵 → dom 𝐹 = 𝐴)
3	1, 2	syl 14	1 ⊢ (𝜑 → dom 𝐹 = 𝐴)

Syntax hints:   → wi 4   = wceq 1290  dom cdm 4452  ⟶wf 5024

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106

This theorem depends on definitions:  df-bi 116  df-fn 5031  df-f 5032

This theorem is referenced by:  fssdmd  5187  fssdm  5188