Description: Utility theorem: index-independent form of df-base . (Contributed by NM, 20-Oct-2012)
Ref | Expression | ||
---|---|---|---|
Assertion | baseid | ⊢ Base = Slot ( Base ‘ ndx ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-base | ⊢ Base = Slot 1 | |
2 | 1nn | ⊢ 1 ∈ ℕ | |
3 | 1 2 | ndxid | ⊢ Base = Slot ( Base ‘ ndx ) |