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The study of mutual visibility has traditionally focused on undirected graphs, asking for the maximum number of vertices that can communicate via shortest paths without intermediate interference from other set members. In this paper, we…

Combinatorics · Mathematics 2026-02-06 Vanja Stojanović

A graph $G$ is $d$-distinguishable if there is a coloring of the vertices with $d$ colors so that only the trivial automorphism preserves the color classes. The smallest such $d$ is the distinguishing number, $\operatorname{Dist}(G)$. The…

Combinatorics · Mathematics 2021-02-01 Debra Boutin , Sally Cockburn , Lauren Keough , Sarah Loeb , K. E. Perry , Puck Rombach

A vertex subset $S$ of a graph $G$ is a general position set of $G$ if no vertex of $S$ lies on a geodesic between two other vertices of $S$. The cardinality of a largest general position set of $G$ is the general position number ${\rm…

Combinatorics · Mathematics 2019-04-17 Bijo S. Anand , Ullas Chandran S. V. , Manoj Changat , Sandi Klavžar , Elias John Thomas

The general position problem is to find the cardinality of a largest vertex subset S such that no triple of vertices of S lie on a common geodesic. For a connected graph G, the cardinality of S is denoted by gp(G) and called gp-number (or…

Combinatorics · Mathematics 2020-02-11 Yan Yao , Mengya He , Shengjin Ji , Guang Li

Given a graph $G$, the general position problem is to find a largest set $S$ of vertices of $G$ such that no three vertices of $S$ lie on a common geodesic. Such a set is called a ${\rm gp}$-$set$ of $G$ and its cardinality is the ${\rm…

Combinatorics · Mathematics 2021-05-11 Paul Manuel , R. Prabha , Sandi Klavžar

A vertex subset $S$ of a graph $G$ is a general position set of $G$ if no vertex of $S$ lies on a geodesic between two other vertices of $S$. The cardinality of a largest general position set of $G$ is the general position number…

The concept of mutual-visibility (MV) has been extended in several directions. A vertex subset $S$ of a graph $G$ is a $k$-distance mutual-visibility ($k$DMV) set if for any two vertices in $S$, there is a geodesic between them of length at…

Combinatorics · Mathematics 2025-10-14 Saneesh Babu , Boštjan Brešar , Aparna Lakshmanan S , Babak Samadi

The mutual-visibility chromatic number of a graph $G$ is the smallest number of colors needed to color the vertices of $G$ such that each color class is a mutual-visibility set. In this paper, we prove that determining the mutual-visibility…

Combinatorics · Mathematics 2026-02-13 Saneesh Babu , Gabriele Di Stefano , Aparna Lakshmanan S

A set of vertices of a graph is said to be in general position if no three vertices from the set lie on a common geodesic. Recently Klav\v{z}ar, Rall and Yero generalized this notion by defining a set of vertices to be in general…

Combinatorics · Mathematics 2024-09-10 Brent Cody , Garrett Moore

If $x\in V(G)$, then $S\subseteq V(G)\setminus\{x\}$ is an $x$-visibility set if for any $y\in S$ there exists a shortest $x,y$-path avoiding $S$. The $x$-visibility number $v_x(G)$ is the maximum cardinality of an $x$-visibility set, and…

Discrete Mathematics · Computer Science 2025-10-23 Dhanya Roy , Gabriele Di Stefano , Sandi Klavžar , Aparna Lakshmanan S

A subset $S$ of vertices of a graph $G$ is a \emph{general position set} if no shortest path in $G$ contains three or more vertices of $S$. In this paper, we generalise a problem of M. Gardner to graph theory by introducing the \emph{lower…

Combinatorics · Mathematics 2024-01-09 Gabriele Di Stefano , Sandi Klavžar , Aditi Krishnakumar , James Tuite , Ismael Yero

The general position number for graphs ask for largest vertex subsets $S$ such that no three vertices are contained on a common shortest path. We examine this problem in the setting of directed graphs. We provide bounds for the general…

Given a graph $G$, the (graph theory) general position problem is to find the maximum number of vertices such that no three vertices lie on a common geodesic. This graph invariant is called the general position number (gp-number for short)…

Combinatorics · Mathematics 2017-10-03 Paul Manuel , Sandi Klavžar

All four invariants of the mutual-visibility problem and, all four invariants of the general position problem are determined for glued binary trees. The number of the corresponding extremal sets is obtained in each of the eight situations.…

Combinatorics · Mathematics 2025-12-10 Dhanya Roy , Sandi Klavžar , Aparna Lakshmanan S

A point visibility graph is a graph induced by a set of points in the plane, where every vertex corresponds to a point, and two vertices are adjacent whenever the two corresponding points are visible from each other, that is, the open…

Computational Geometry · Computer Science 2019-02-05 Jean Cardinal , Udo Hoffmann

Given a graph $G$, a subset $M\subseteq V(G)$ is a mutual-visibility (MV) set if for every $u,v\in M$, there exists a $u,v$-geodesic whose internal vertices are not in $M$. We investigate proper vertex colorings of graphs whose color…

Combinatorics · Mathematics 2025-05-08 Boštjan Brešar , Iztok Peterin , Babak Samadi , Ismael G. Yero

Getting inspired by the famous no-three-in-line problem and by the general position subset selection problem from discrete geometry, the same is introduced into graph theory as follows. A set $S$ of vertices in a graph $G$ is a general…

Combinatorics · Mathematics 2020-04-10 Elias John Thomas , Ullas Chandran S. V.

In multiagent systems, effective coordination, coverage, and communication often rely on the concept of visibility between agents or nodes within the system. Graph-theoretically, for any subset $X$ of vertices of a graph $G$, two vertices…

Combinatorics · Mathematics 2025-09-03 Tonny K B , Shikhi M

A subset $S$ of vertices of a graph $G$ is in \emph{general position} if no shortest path in $G$ contains three vertices of $S$. The \emph{general position problem} consists of finding the number of vertices in a largest general position…

Combinatorics · Mathematics 2024-05-01 Eartha Kruft Welton , Sharif Khudairi , James Tuite

The general position number ${\rm gp}(G)$ of a connected graph $G$ is the cardinality of a largest set $S$ of vertices such that no three distinct vertices from $S$ lie on a common geodesic; such sets are refereed to as gp-sets of $G$. The…

Combinatorics · Mathematics 2021-05-11 Sandi Klavžar , Balázs Patkós , Gregor Rus , Ismael G. Yero