Theorem frege54b

Description: Reflexive equality of sets. The content of x is identical with the content of x . Part of Axiom 54 of Frege1879 p. 50. Slightly specialized version of eqid . (Contributed by RP, 24-Dec-2019) (Proof modification is discouraged.)

	Ref	Expression
Assertion	frege54b	|- x = x

Proof

Step	Hyp	Ref	Expression
1		ax-frege54c	|- x = x