Theorem fofun 5127

Description: An onto mapping is a function. (Contributed by NM, 29-Mar-2008.)

Assertion

Ref	Expression
fofun	⊢ (𝐹:𝐴–onto→𝐵 → Fun 𝐹)

Proof of Theorem fofun

Step	Hyp	Ref	Expression
1		fof 5126	. 2 ⊢ (𝐹:𝐴–onto→𝐵 → 𝐹:𝐴⟶𝐵)
2		ffun 5068	. 2 ⊢ (𝐹:𝐴⟶𝐵 → Fun 𝐹)
3	1, 2	syl 14	1 ⊢ (𝐹:𝐴–onto→𝐵 → Fun 𝐹)

Syntax hints:   → wi 4  Fun wfun 4916  ⟶wf 4918  –onto→wfo 4920

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-in 2979  df-ss 2986  df-fn 4925  df-f 4926  df-fo 4928

This theorem is referenced by:  foimacnv  5164  resdif  5168  fococnv2  5172  fornex  5762