Description: Sufficient condition for being a partial function. (Contributed by NM, 31-Dec-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | elpm2r | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fdm | |
|
2 | 1 | feq2d | |
3 | 1 | sseq1d | |
4 | 2 3 | anbi12d | |
5 | 4 | adantr | |
6 | 5 | ibir | |
7 | elpm2g | |
|
8 | 6 7 | imbitrrid | |
9 | 8 | imp | |