Theorem dsndx

Description: Index value of the df-ds slot. (Contributed by Mario Carneiro, 14-Aug-2015) (New usage is discouraged.)

	Ref	Expression
Assertion	dsndx	⊢ ( dist ‘ ndx ) = ; 1 2

Proof

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