Connected graph

Set

context $V,E$ … set
definiendum $\langle V,E,\psi\rangle \in \mathrm{it}(E,V) $
postulate $\langle V,E,\psi\rangle $ … undirected graph
range $ X\cap Y=\emptyset $
range $ X\cup Y=V $
range $ x\in X $
range $ y\in Y $
postulate $ \forall X,Y. \exists x,y.\ \{x,y\}\in\mathrm{im}\ \psi $

Discussion

Parents

Subset of

Undirected graph