Directed graph

Set

context $ V,E $ … set
definiendum $ \langle V,\langle E,\psi\rangle\rangle \in \mathrm{it}(E,V) $
postulate $ \psi $ … function
postulate $ \mathrm{dom}(\psi)=E $
postulate $ \forall (e\in E).\ \exists (u,v\in V).\ \psi(e) = \langle v,u \rangle $

Discussion

Parents

Subset of

Graph

Context

Function