Quasi-order


Definition

\(\mathcal{R}\) is reflexive
\(\forall x,y \in S : x{\mathcal{R}}x\)
\(\forall x,y,z \in S : x{\mathcal{R}}y \wedge y{\mathcal{R}}z \Rightarrow x{\mathcal{R}}z\)

See also

Session HOL-Lattice

Proper supersets