Theorem prtlem80

Description: Lemma for prter2 . (Contributed by Rodolfo Medina, 17-Oct-2010)

	Ref	Expression
Assertion	prtlem80	⊢ ( 𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ ( 𝐶 ∖ { 𝐴 } ) )

Proof

Step	Hyp	Ref	Expression
1		neldifsnd	⊢ ( 𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ ( 𝐶 ∖ { 𝐴 } ) )