### 3.7.147. Minimum feedback vertex set

Denotes the fact that a constraint is related to the minimum feedback vertex set problem: given a connected graph $G=\left(V,E\right)$, find out a minimum cardinality subset ${V}^{\text{'}}$ of $V$ such that the graph ${G}^{\text{'}}$ induced by $V\setminus {V}^{\text{'}}$ does not contain any cycle. A survey on the feedback vertex set problem is given in