Theorem qseq2d

Description: Equality theorem for quotient set, deduction form. (Contributed by Peter Mazsa, 27-May-2021)

	Ref	Expression
Hypothesis	qseq1d.1	$$⊢\phi \to A=B$$
Assertion	qseq2d	$$⊢\phi \to C/A=C/B$$

Proof

Step	Hyp	Ref	Expression
1		qseq1d.1	$$⊢\phi \to A=B$$
2		qseq2	$$⊢A=B\to C/A=C/B$$
3	1 2	syl	$$⊢\phi \to C/A=C/B$$