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IC-planar graphs are those graphs that admit a drawing where no two crossed edges share an end-vertex and each edge is crossed at most once. They are a proper subfamily of the 1-planar graphs. Given an embedded IC-planar graph $G$ with $n$…

Computational Geometry · Computer Science 2016-07-19 Franz J. Brandenburg , Walter Didimo , William S. Evans , Philipp Kindermann , Giuseppe Liotta , Fabrizio Montecchiani

We study the long-standing open problem of efficiently testing rectilinear planarity of series-parallel graphs (SP-graphs) in the variable embedding setting. A key ingredient behind the design of a linear-time testing algorithm for…

Data Structures and Algorithms · Computer Science 2021-10-04 Walter Didimo , Michael Kaufmann , Giuseppe Liotta , Giacomo Ortali

In this paper we study two problems related to the drawing of level graphs, that is, T-LEVEL PLANARITY and CLUSTERED-LEVEL PLANARITY. We show that both problems are NP-complete in the general case and that they become polynomial-time…

Data Structures and Algorithms · Computer Science 2014-06-26 Patrizio Angelini , Giordano Da Lozzo , Giuseppe Di Battista , Fabrizio Frati , Vincenzo Roselli

Planar Embedding is a drawing of a graph on the plane such that the edges do not intersect each other except at the vertices. We know that testing the planarity of a graph and computing its embedding (if it exists), can efficiently be…

Data Structures and Algorithms · Computer Science 2023-07-19 Samir Datta , Asif Khan , Anish Mukherjee

We consider variants of the clustered planarity problem for level-planar drawings. So far, only convex clusters have been studied in this setting. We introduce two new variants that both insist on a level-planar drawing of the input graph…

Computational Geometry · Computer Science 2024-02-21 Simon D. Fink , Matthias Pfretzschner , Ignaz Rutter , Marie Diana Sieper

In this paper we settle the computational complexity of two open problems related to the extension of the notion of level planarity to surfaces different from the plane. Namely, we show that the problems of testing the existence of a level…

Data Structures and Algorithms · Computer Science 2016-08-30 Patrizio Angelini , Giordano Da Lozzo , Giuseppe Di Battista , Fabrizio Frati , Maurizio Patrignani , Ignaz Rutter

Hierarchical embedding constraints define a set of allowed cyclic orders for the edges incident to the vertices of a graph. These constraints are expressed in terms of FPQ-trees. FPQ-trees are a variant of PQ-trees that includes F-nodes in…

Data Structures and Algorithms · Computer Science 2019-11-19 Giuseppe Liotta , Ignaz Rutter , Alessandra Tappini

We give a distributed algorithm in the {\sf CONGEST} model for property testing of planarity with one-sided error in general (unbounded-degree) graphs. Following Censor-Hillel et al. (DISC 2016), who recently initiated the study of property…

Distributed, Parallel, and Cluster Computing · Computer Science 2019-08-15 Reut Levi , Moti Medina , Dana Ron

We introduce the problem Synchronized Planarity. Roughly speaking, its input is a loop-free multi-graph together with synchronization constraints that, e.g., match pairs of vertices of equal degree by providing a bijection between their…

Data Structures and Algorithms · Computer Science 2021-07-23 Thomas Bläsius , Simon D. Fink , Ignaz Rutter

A rectangle visibility representation (RVR) of a graph consists of an assignment of axis-aligned rectangles to vertices such that for every edge there exists a horizontal or vertical line of sight between the rectangles assigned to its…

Computational Geometry · Computer Science 2019-09-04 Therese Biedl , Giuseppe Liotta , Fabrizio Montecchiani

Fan-planar graphs were recently introduced as a generalization of 1-planar graphs. A graph is fan-planar if it can be embedded in the plane, such that each edge that is crossed more than once, is crossed by a bundle of two or more edges…

Computational Geometry · Computer Science 2014-09-02 Michael A. Bekos , Sabine Cornelsen , Luca Grilli , Seok-Hee Hong , Michael Kaufmann

We consider upward-planar layered drawings of directed graphs, i.e., crossing-free drawings in which each edge is drawn as a y-monotone curve going upward from its tail to its head, and the y-coordinates of the vertices are integers. The…

Computational Geometry · Computer Science 2026-05-04 Patrizio Angelini , Sabine Cornelsen , Giordano Da Lozzo , Fabrizio Frati , Philipp Kindermann , Ignaz Rutter , Johannes Zink

A (possibly denerate) drawing of a graph $G$ in the plane is approximable by an embedding if it can be turned into an embedding by an arbitrarily small perturbation. We show that testing, whether a straight-line drawing of a planar graph…

Computational Geometry · Computer Science 2017-05-09 Radoslav Fulek

In this paper, we give polynomial-time algorithms that can take a graph G with a given combinatorial embedding on an orientable surface S of genus g and produce a planar drawing of G in R^2, with a bounding face defined by a polygonal…

Computational Geometry · Computer Science 2009-08-13 Christian A. Duncan , Michael T. Goodrich , Stephen G. Kobourov

A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by no more than one other edge (and any pair of crossing edges cross only once). A non-1-planar graph $G$ is minimal if the graph $G-e$ is 1-planar for every…

Combinatorics · Mathematics 2011-10-24 Vladimir P. Korzhik , Bojan Mohar

We study the simultaneous embeddability of a pair of partitions of the same underlying set into disjoint blocks. Each element of the set is mapped to a point in the plane and each block of either of the two partitions is mapped to a region…

Computational Geometry · Computer Science 2014-08-27 Jan Christoph Athenstädt , Tanja Hartmann , Martin Nöllenburg

Graph representation learning is a fast-growing field where one of the main objectives is to generate meaningful representations of graphs in lower-dimensional spaces. The learned embeddings have been successfully applied to perform various…

Machine Learning · Computer Science 2021-12-21 Md. Khaledur Rahman , Ariful Azad

A graph is 1-planar if it can be drawn on a plane so that each edge is crossed by at most one other edge. In this paper, we first give a useful structural theorem for 1-planar graphs, and then apply it to the list edge and list total…

Combinatorics · Mathematics 2019-12-17 Xin Zhang , Bei Niu , Jiguo Yu

A strict orthogonal drawing of a graph $G=(V, E)$ in $\mathbb{R}^2$ is a drawing of $G$ such that each vertex is mapped to a distinct point and each edge is mapped to a horizontal or vertical line segment. A graph $G$ is $HV$-restricted if…

Computational Geometry · Computer Science 2019-04-16 Stephane Durocher , Stefan Felsner , Saeed Mehrabi , Debajyoti Mondal

We study upward pointset embeddings (UPSEs) of planar $st$-graphs. Let $G$ be a planar $st$-graph and let $S \subset \mathbb{R}^2$ be a pointset with $|S|= |V(G)|$. An UPSE of $G$ on $S$ is an upward planar straight-line drawing of $G$ that…

Data Structures and Algorithms · Computer Science 2025-01-06 Carlos Alegria , Susanna Caroppo , Giordano Da Lozzo , Marco D'Elia , Giuseppe Di Battista , Fabrizio Frati , Fabrizio Grosso , Maurizio Patrignani