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