Theorem relssr

Description: The subset relation is a relation. (Contributed by Peter Mazsa, 1-Aug-2019)

	Ref	Expression
Assertion	relssr	$$⊢\mathrm{Rel}\mathrm{S}$$

Proof

Step	Hyp	Ref	Expression
1		df-ssr	$$⊢\mathrm{S}=\left\{⟨x,y⟩|x\subseteq y\right\}$$
2	1	relopabi	$$⊢\mathrm{Rel}\mathrm{S}$$