Theorem fndmd 39953

Description: The domain of a function. (Contributed by Glauco Siliprandi, 23-Oct-2021.)

Hypothesis

Ref	Expression
fndmd.1	⊢ (𝜑 → 𝐹 Fn 𝐴)

Assertion

Ref	Expression
fndmd	⊢ (𝜑 → dom 𝐹 = 𝐴)

Proof of Theorem fndmd

Step	Hyp	Ref	Expression
1		fndmd.1	. 2 ⊢ (𝜑 → 𝐹 Fn 𝐴)
2		fndm 6130	. 2 ⊢ (𝐹 Fn 𝐴 → dom 𝐹 = 𝐴)
3	1, 2	syl 17	1 ⊢ (𝜑 → dom 𝐹 = 𝐴)

Syntax hints:   → wi 4   = wceq 1630  dom cdm 5249   Fn wfn 6026

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 197  df-an 383  df-fn 6034

This theorem is referenced by:  fvelimad  39970  fnfvimad  39971  limsupequzlem  40466  climrescn  40492  smflimmpt  41530  smflimsuplem7  41546