“…In this context, the graph partitioning problem is NP-complete [24], and there are available strategies based on spectral [25] (eigenproblem in [26]), combinatorial [27], geometric [28] and multi-level [29] heuristics. Partitioning of the graph vertices leads to recognition the of 2-subcolorable [30], bipartite [31], cluster [32], dominable [33], monopolar [34], r-partite [35], split [36], unipolar [37], trapezoid [38] and graphical algorithms (etc.) working efficiently with special classes of graphs that have been devised (for monopolar and 2-subcolorable in [30]; for unipolar and generalized split in [39]; for partitioning a big graph into k sub-graphs in [40,41]; for graph that does not contain an induced subgraph, a claw in [42]).…”