Theorem eliminable1 32840

Description: A theorem used to prove the base case of the Eliminability Theorem (see section comment). (Contributed by BJ, 19-Oct-2019.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
eliminable1	|- ( y e. { x | ph } <-> [ y / x ] ph )

Proof of Theorem eliminable1

Step	Hyp	Ref	Expression
1		df-clab 2609	1 |- ( y e. { x | ph } <-> [ y / x ] ph )

Syntax hints:   <-> wb 196   [wsb 1880   e. wcel 1990   {cab 2608

This theorem depends on definitions:  df-clab 2609

This theorem is referenced by: (None)