Description: Any function is a mapping into _V . (Contributed by NM, 31-Oct-1995) (Proof shortened by Andrew Salmon, 17-Sep-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | dffn2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssv | |
|
2 | 1 | biantru | |
3 | df-f | |
|
4 | 2 3 | bitr4i | |