Theorem nfab1

Description: Bound-variable hypothesis builder for a class abstraction. (Contributed by Mario Carneiro, 11-Aug-2016)

	Ref	Expression
Assertion	nfab1	$$⊢\underset{\_}{Ⅎ}x\left\{x|\phi \right\}$$

Proof

Step	Hyp	Ref	Expression
1		nfsab1	$$⊢Ⅎxy\in \left\{x|\phi \right\}$$
2	1	nfci	$$⊢\underset{\_}{Ⅎ}x\left\{x|\phi \right\}$$