Theorem f1dm 5262

Description: The domain of a one-to-one mapping. (Contributed by set.mm contributors, 8-Mar-2014.)

Assertion

Ref	Expression
f1dm	⊢ (F:A–1-1→B → dom F = A)

Proof of Theorem f1dm

Step	Hyp	Ref	Expression
1		f1fn 5260	. 2 ⊢ (F:A–1-1→B → F Fn A)
2		fndm 5183	. 2 ⊢ (F Fn A → dom F = A)
3	1, 2	syl 15	1 ⊢ (F:A–1-1→B → dom F = A)

Syntax hints:   → wi 4   = wceq 1642  dom cdm 4773   Fn wfn 4777  –1-1→wf1 4779

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 177  df-an 360  df-fn 4791  df-f 4792  df-f1 4793

This theorem is referenced by:  fun11iun  5306