Metamath Proof Explorer


Theorem dff1o2

Description: Alternate definition of one-to-one onto function. (Contributed by NM, 10-Feb-1997) (Proof shortened by Andrew Salmon, 22-Oct-2011)

Ref Expression
Assertion dff1o2 F : A 1-1 onto B F Fn A Fun F -1 ran F = B

Proof

Step Hyp Ref Expression
1 df-f1o F : A 1-1 onto B F : A 1-1 B F : A onto B
2 df-f1 F : A 1-1 B F : A B Fun F -1
3 df-fo F : A onto B F Fn A ran F = B
4 2 3 anbi12i F : A 1-1 B F : A onto B F : A B Fun F -1 F Fn A ran F = B
5 anass F : A B Fun F -1 F Fn A ran F = B F : A B Fun F -1 F Fn A ran F = B
6 3anan12 F Fn A Fun F -1 ran F = B Fun F -1 F Fn A ran F = B
7 6 anbi1i F Fn A Fun F -1 ran F = B F : A B Fun F -1 F Fn A ran F = B F : A B
8 eqimss ran F = B ran F B
9 df-f F : A B F Fn A ran F B
10 9 biimpri F Fn A ran F B F : A B
11 8 10 sylan2 F Fn A ran F = B F : A B
12 11 3adant2 F Fn A Fun F -1 ran F = B F : A B
13 12 pm4.71i F Fn A Fun F -1 ran F = B F Fn A Fun F -1 ran F = B F : A B
14 ancom F : A B Fun F -1 F Fn A ran F = B Fun F -1 F Fn A ran F = B F : A B
15 7 13 14 3bitr4ri F : A B Fun F -1 F Fn A ran F = B F Fn A Fun F -1 ran F = B
16 5 15 bitri F : A B Fun F -1 F Fn A ran F = B F Fn A Fun F -1 ran F = B
17 4 16 bitri F : A 1-1 B F : A onto B F Fn A Fun F -1 ran F = B
18 1 17 bitri F : A 1-1 onto B F Fn A Fun F -1 ran F = B