Metamath Proof Explorer

Theorem unt0

Description: The null set is untangled. (Contributed by Scott Fenton, 10-Mar-2011) (Proof shortened by Andrew Salmon, 27-Aug-2011)

Ref Expression
Assertion unt0 
|- A. x e. (/) -. x e. x

Proof

Step Hyp Ref Expression
1 ral0 
 |-  A. x e. (/) -. x e. x