Theorem bj-tagn0

Description: The tagging of a class is nonempty. (Contributed by BJ, 6-Apr-2019)

	Ref	Expression
Assertion	bj-tagn0	⊢ tag 𝐴 ≠ ∅

Proof

Step	Hyp	Ref	Expression
1		bj-0eltag	⊢ ∅ ∈ tag 𝐴
2	1	ne0ii	⊢ tag 𝐴 ≠ ∅