## Regular graph

### Set

 context $V,E$ … set
 definiendum $\langle V,E,\psi\rangle \in \mathrm{it}(E,V)$
 inclusion $\langle V,E,\psi\rangle$ … undirected graph
 range $k\in \mathbb N$ range $v\in V$
 postulate $\exists k.\ \forall v.\ d(v)=k$