Metamath Proof Explorer


Theorem fin

Description: Mapping into an intersection. (Contributed by NM, 14-Sep-1999) (Proof shortened by Andrew Salmon, 17-Sep-2011)

Ref Expression
Assertion fin F:ABCF:ABF:AC

Proof

Step Hyp Ref Expression
1 ssin ranFBranFCranFBC
2 1 anbi2i FFnAranFBranFCFFnAranFBC
3 anandi FFnAranFBranFCFFnAranFBFFnAranFC
4 2 3 bitr3i FFnAranFBCFFnAranFBFFnAranFC
5 df-f F:ABCFFnAranFBC
6 df-f F:ABFFnAranFB
7 df-f F:ACFFnAranFC
8 6 7 anbi12i F:ABF:ACFFnAranFBFFnAranFC
9 4 5 8 3bitr4i F:ABCF:ABF:AC