Theorem unifid

Description: Utility theorem: index-independent form of df-unif . (Contributed by Thierry Arnoux, 17-Dec-2017)

	Ref	Expression
Assertion	unifid	⊢ UnifSet = Slot ( UnifSet ‘ ndx )

Proof

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