Description: Utility theorem: index-independent form of df-ds . (Contributed by Mario Carneiro, 23-Dec-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | dsid | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-ds | |
|
2 | 1nn0 | |
|
3 | 2nn | |
|
4 | 2 3 | decnncl | |
5 | 1 4 | ndxid | |