Theorem itvndx

Description: Index value of the Interval (segment) slot. Use ndxarg . (Contributed by Thierry Arnoux, 24-Aug-2017)

	Ref	Expression
Assertion	itvndx	⊢ ( Itv ‘ ndx ) = ; 1 6

Proof

Step	Hyp	Ref	Expression
1		df-itv	⊢ Itv = Slot ; 1 6
2		1nn0	⊢ 1 ∈ ℕ0
3		6nn	⊢ 6 ∈ ℕ
4	2 3	decnncl	⊢ ; 1 6 ∈ ℕ
5	1 4	ndxarg	⊢ ( Itv ‘ ndx ) = ; 1 6