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Related papers: On some subclasses of circular-arc catch digraphs

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Grid intersection graphs are the intersection graphs of vertical and horizontal segments in the plane. When the bottom and respectively left endpoints of the vertical and horizontals segments belong to a line with negative slope, the graph…

Discrete Mathematics · Computer Science 2022-01-27 Irena Rusu

The class of intersection bigraphs of unit intervals of the real line whose ends may be open or closed is called a class of mixed unit interval bigraphs. This class of bigraphs is a strict superclass of the class of unit interval bigraphs.…

Discrete Mathematics · Computer Science 2026-05-27 Ashok Kumar Das , Rajkamal Sahu , Amina Khatun

Distance-regular graphs are a class of regualr graphs with pretty combinatorial symmetry. In 2007, Miklavi\v{c} and Poto\v{c}nik proposed the problem of charaterizing distance-regular Cayley graphs, which can be viewed as a natural…

Combinatorics · Mathematics 2023-11-15 Xueyi Huang , Lu Lu , Xiongfeng Zhan

We employ random geometric digraphs to construct semi-parametric classifiers. These data-random digraphs are from parametrized random digraph families called proximity catch digraphs (PCDs). A related geometric digraph family, class cover…

Machine Learning · Computer Science 2017-05-23 Artür Manukyan , Elvan Ceyhan

McConnell [FOCS 2001] presented a flipping transformation from circular-arc graphs to interval graphs with certain patterns of representations. Beyond its algorithmic implications, this transformation is instrumental in identifying all…

Combinatorics · Mathematics 2025-04-30 Yixin Cao , Tomasz Krawczyk

An interval graph is proper iff it has a representation in which no interval contains another. Fred Roberts characterized the proper interval graphs as those containing no induced star $K_{1,3}$. Proskurowski and Telle have studied…

Combinatorics · Mathematics 2011-10-03 Jeffrey Beyerl , Robert E. Jamison

Proximity catch digraphs (PCDs) are based on proximity maps which yield proximity regions and are special types of proximity graphs. PCDs are based on the relative allocation of points from two or more classes in a region of interest and…

Probability · Mathematics 2009-03-31 Elvan Ceyhan

Stick graphs are intersection graphs of horizontal and vertical line segments that all touch a line of slope -1 and lie above this line. De Luca et al. [GD'18] considered the recognition problem of stick graphs when no order is given…

Computational Geometry · Computer Science 2020-06-23 Steven Chaplick , Philipp Kindermann , Andre Löffler , Florian Thiele , Alexander Wolff , Alexander Zaft , Johannes Zink

We introduce the class of interval $H$-graphs, which is the generalization of interval graphs, particularly interval bigraphs. For a fixed graph $H$ with vertices $a_1,a_2,\dots,a_k$, we say that an input graph $G$ with given partition…

Discrete Mathematics · Computer Science 2025-03-04 Haiko Müller , Arash Rafiey

If each vertex of an acyclic digraph has indegree at most $i$ and outdegree at most $j$, then it is called an $(i,j)$ digraph, which was introduced by Hefner~{\it et al.}~(1991). Whereas Hefner~{\it et al.} characterized $(i,j)$ digraphs…

Combinatorics · Mathematics 2025-07-18 Hojin Chu , Suh-Ryung Kim

We study a new kind of proximity graphs called proportional-edge proximity catch digraphs (PCDs)in a randomized setting. PCDs are a special kind of random catch digraphs that have been developed recently and have applications in statistical…

Combinatorics · Mathematics 2010-03-30 Elvan Ceyhan

A Helly circular-arc model M = (C,A) is a circle C together with a Helly family \A of arcs of C. If no arc is contained in any other, then M is a proper Helly circular-arc model, if every arc has the same length, then M is a unit Helly…

Discrete Mathematics · Computer Science 2015-03-19 Min Chih Lin , Francisco J. Soulignac , Jayme L. Szwarcfiter

A circular-arc graph is the intersection graph of arcs of a circle. It is a well-studied graph model with numerous natural applications. A certifying algorithm is an algorithm that outputs a certificate, along with its answer (be it…

Discrete Mathematics · Computer Science 2014-08-13 Mathew Francis , Pavol Hell , Juraj Stacho

The class of closed graphs by a linear ordering on their sets of vertices is investigated. A recent characterization of such a class of graphs is analyzed by using tools from the proper interval graph theory.

Combinatorics · Mathematics 2015-09-23 Marilena Crupi

Corneil, Olariu, and Stewart [SODA 1998; SIAM Journal on Discrete Mathematics 2009] presented a recognition algorithm for interval graphs by six graph searches. Li and Wu [Discrete Mathematics \& Theoretical Computer Science 2014]…

Data Structures and Algorithms · Computer Science 2020-10-08 Yixin Cao

In 2020, Cameron et al. introduced the restricted numerical range of a digraph (directed graph) as a tool for characterizing digraphs and studying their algebraic connectivity. In particular, digraphs with a restricted numerical range of a…

Combinatorics · Mathematics 2021-06-03 Thomas R. Cameron , H. Tracy Hall , Ben Small , Alexander Wiedemann

Chordal graphs are the graphs in which every cycle of length at least four has a chord. A set $S$ is a vertex separator for vertices $a$ and $b$ if the removal of $S$ of the graph separates $a$ and $b$ into distinct connected components. A…

Discrete Mathematics · Computer Science 2018-03-22 Sérgio H. Nogueira , Vinicius F. dos Santos

A simple-triangle graph (also known as a PI graph) is the intersection graph of a family of triangles defined by a point on a horizontal line and an interval on another horizontal line. The recognition problem for simple-triangle graphs was…

Discrete Mathematics · Computer Science 2017-04-04 Asahi Takaoka

A cocomparability graph is a graph whose complement admits a transitive orientation. An interval graph is the intersection graph of a family of intervals on the real line. In this paper we investigate the relationships between interval and…

Discrete Mathematics · Computer Science 2016-11-08 Jérémie Dusart , Michel Habib , Derek G. Corneil

A graph is concave-round if its vertices can be circularly enumerated so that the closed neighbourhood of each vertex is an interval in the enumeration. In this work, we give a minimal forbidden induced subgraph characterization for the…

Combinatorics · Mathematics 2016-11-08 Martín D. Safe