Metamath Proof Explorer


Theorem f11o

Description: Relationship between one-to-one and one-to-one onto function. (Contributed by NM, 4-Apr-1998)

Ref Expression
Hypothesis f11o.1 F V
Assertion f11o F : A 1-1 B x F : A 1-1 onto x x B

Proof

Step Hyp Ref Expression
1 f11o.1 F V
2 1 ffoss F : A B x F : A onto x x B
3 2 anbi1i F : A B Fun F -1 x F : A onto x x B Fun F -1
4 df-f1 F : A 1-1 B F : A B Fun F -1
5 dff1o3 F : A 1-1 onto x F : A onto x Fun F -1
6 5 anbi1i F : A 1-1 onto x x B F : A onto x Fun F -1 x B
7 an32 F : A onto x Fun F -1 x B F : A onto x x B Fun F -1
8 6 7 bitri F : A 1-1 onto x x B F : A onto x x B Fun F -1
9 8 exbii x F : A 1-1 onto x x B x F : A onto x x B Fun F -1
10 19.41v x F : A onto x x B Fun F -1 x F : A onto x x B Fun F -1
11 9 10 bitri x F : A 1-1 onto x x B x F : A onto x x B Fun F -1
12 3 4 11 3bitr4i F : A 1-1 B x F : A 1-1 onto x x B