Theorem itvndx

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

	Ref	Expression
Assertion	itvndx	$$⊢\mathrm{Itv}\left(\mathrm{ndx}\right)=16$$

Proof

Step	Hyp	Ref	Expression
1		df-itv	$$⊢\mathrm{Itv}=\mathrm{Slot}16$$
2		1nn0	$$⊢1\in {\mathbb{N}}_0$$
3		6nn	$$⊢6\in \mathbb{N}$$
4	2 3	decnncl	$$⊢16\in \mathbb{N}$$
5	1 4	ndxarg	$$⊢\mathrm{Itv}\left(\mathrm{ndx}\right)=16$$