Theorem lngid

Description: Utility theorem: index-independent form of df-lng . (Contributed by Thierry Arnoux, 27-Mar-2019)

	Ref	Expression
Assertion	lngid	⊢ LineG = Slot ( LineG ‘ ndx )

Proof

Step	Hyp	Ref	Expression
1		df-lng	⊢ LineG = Slot ; 1 7
2		1nn0	⊢ 1 ∈ ℕ0
3		7nn	⊢ 7 ∈ ℕ
4	2 3	decnncl	⊢ ; 1 7 ∈ ℕ
5	1 4	ndxid	⊢ LineG = Slot ( LineG ‘ ndx )