Theorem lngndx

Description: Index value of the "line" slot. Use ndxarg . (Contributed by Thierry Arnoux, 27-Mar-2019)

	Ref	Expression
Assertion	lngndx	⊢ ( LineG ‘ ndx ) = ; 1 7

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	ndxarg	⊢ ( LineG ‘ ndx ) = ; 1 7