  Entanglement is a digraph complexity measure that origins in fixed-point
theory. Its purpose is to count the nested depth of cycles in digraphs.
  In this paper we prove that the class of undirected graphs of entanglement at
most $k$, for arbitrary fixed $k \in \mathbb{N}$, is closed under taking
minors. Our proof relies on the game theoretic characterization of entanglement
in terms of Robber and Cops games.
