Sketched Representations and Orthogonal Planarity of Bounded Treewidth Graphs

08/14/2019

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by   Emilio Di Giacomo, et al.

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Given a planar graph G and an integer b, OrthogonalPlanarity is the problem of deciding whether G admits an orthogonal drawing with at most b bends in total. We show that OrthogonalPlanarity can be solved in polynomial time if G has bounded treewidth. Our proof is based on an FPT algorithm whose parameters are the number of bends, the treewidth and the number of degree-2 vertices of G. This result is based on the concept of sketched orthogonal representation that synthetically describes a family of equivalent orthogonal representations. Our approach can be extended to related problems such as HV-Planarity and FlexDraw. In particular, both OrthogonalPlanarity and HV-Planarity can be decided in O(n^3 log n) time for series-parallel graphs, which improves over the previously known O(n^4) bounds.