Description: Bound-variable hypothesis builder for an onto function. (Contributed by NM, 16-May-2004)
Ref | Expression | ||
---|---|---|---|
Hypotheses | nffo.1 | |
|
nffo.2 | |
||
nffo.3 | |
||
Assertion | nffo | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nffo.1 | |
|
2 | nffo.2 | |
|
3 | nffo.3 | |
|
4 | df-fo | |
|
5 | 1 2 | nffn | |
6 | 1 | nfrn | |
7 | 6 3 | nfeq | |
8 | 5 7 | nfan | |
9 | 4 8 | nfxfr | |