Metamath Proof Explorer


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