TheoremBase

No Set Is an Element of Itself, Nor Is Its Singleton, and No Set Equals Its Singleton

From the axiom of foundation: no set is an element of itself, the singleton of a set is not an element of it, and no set equals its own singleton.

Statement

In the setting of Routine Facts Used Without Citation: Arithmetic, Maps, Predicativity and Indices, let XX be a set, and let {X}\{X\} be its singleton.

X∉XX\notin X.

{X}∉X\{X\}\notin X.

X≠{X}X\neq\{X\}.

Proofs

Log in to submit a proof.

Loading...

Citations

Loading…

Dependencies

Loading…

Related

0 relations

Curated associations between results. These are editable and subjective — they do not replace the dependency graph, which is derived from the references in the text.

No relations recorded yet.

Comments

Log in to comment.

Loading…