Theorem csbvargi

Description: The proper substitution of a class for a setvar variable results in the class (if the class exists), in inference form of csbvarg . (Contributed by Giovanni Mascellani, 30-May-2019)

	Ref	Expression
Hypothesis	csbvargi.1	$$⊢A\in \mathrm{V}$$
Assertion	csbvargi	$$⊢⦋A/x⦌x=A$$

Proof

Step	Hyp	Ref	Expression
1		csbvargi.1	$$⊢A\in \mathrm{V}$$
2		csbvarg	$$⊢A\in \mathrm{V}\to ⦋A/x⦌x=A$$
3	1 2	ax-mp	$$⊢⦋A/x⦌x=A$$