Description: Utility theorem: index-independent form of df-itv . (Contributed by Thierry Arnoux, 24-Aug-2017)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | itvid | |- Itv = Slot ( Itv ` ndx ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-itv | |- Itv = Slot ; 1 6 |
|
| 2 | 1nn0 | |- 1 e. NN0 |
|
| 3 | 6nn | |- 6 e. NN |
|
| 4 | 2 3 | decnncl | |- ; 1 6 e. NN |
| 5 | 1 4 | ndxid | |- Itv = Slot ( Itv ` ndx ) |