Description: If the addition operation is already a function, the functionalization of it is equal to the original operation. (Contributed by Mario Carneiro, 14-Aug-2015)
Ref | Expression | ||
---|---|---|---|
Hypotheses | plusffval.1 | ||
plusffval.2 | |||
plusffval.3 | |||
Assertion | plusfeq |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | plusffval.1 | ||
2 | plusffval.2 | ||
3 | plusffval.3 | ||
4 | 1 2 3 | plusffval | |
5 | fnov | ||
6 | 5 | biimpi | |
7 | 4 6 | eqtr4id |