Description: Membership law for "the unique element in A such that ph ". (Contributed by NM, 21-Aug-2011) (Revised by Mario Carneiro, 23-Dec-2016)
Ref | Expression | ||
---|---|---|---|
Assertion | riotacl2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-reu | |
|
2 | iotacl | |
|
3 | 1 2 | sylbi | |
4 | df-riota | |
|
5 | df-rab | |
|
6 | 3 4 5 | 3eltr4g | |