Description: Mapping into an intersection. (Contributed by NM, 14-Sep-1999) (Proof shortened by Andrew Salmon, 17-Sep-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | fin | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssin | |
|
2 | 1 | anbi2i | |
3 | anandi | |
|
4 | 2 3 | bitr3i | |
5 | df-f | |
|
6 | df-f | |
|
7 | df-f | |
|
8 | 6 7 | anbi12i | |
9 | 4 5 8 | 3bitr4i | |