Description: Utility theorem: index-independent form of df-edgf . (Contributed by AV, 16-Nov-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | edgfid | ⊢ .ef = Slot ( .ef ‘ ndx ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | df-edgf | ⊢ .ef = Slot ; 1 8 | |
| 2 | 1nn0 | ⊢ 1 ∈ ℕ0 | |
| 3 | 8nn | ⊢ 8 ∈ ℕ | |
| 4 | 2 3 | decnncl | ⊢ ; 1 8 ∈ ℕ | 
| 5 | 1 4 | ndxid | ⊢ .ef = Slot ( .ef ‘ ndx ) |