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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…

Let $G=(V(G),E(G))$ be a simple graph, and let $U\subseteq V(G)$. Two distinct vertices $x,y\in U$ are $U$-mutually visible if $G$ contains a shortest $x$-$y$ path that is internally disjoint from $U$. $U$ is called a mutual-visibility set…

Combinatorics · Mathematics 2025-06-04 J. Leaños , M. Lomelí-Haro , Christophe Ndjatchi , L. M. Ríos-Castro

Let $G$ be a graph and $X\subseteq V(G)$. Then $X$ is a mutual-visibility set if each pair of vertices from $X$ is connected by a geodesic with no internal vertex in $X$. The mutual-visibility number $\mu(G)$ of $G$ is the cardinality of a…

Combinatorics · Mathematics 2024-04-19 Serafino Cicerone , Gabriele Di Stefano , Sandi Klavžar , Ismael G. Yero

Let $G$ be a graph and $M \subseteq V(G)$. Vertices $x, y \in M$ are $M$-visible if there exists a shortest $x,y$-path of $G$ that does not pass through any vertex of $M \setminus \{x, y \}$. We say that $M$ is a mutual-visibility set if…

Combinatorics · Mathematics 2024-05-10 Danilo Korže , Aleksander Vesel

The classical no-three-in-line problem is to find the maximum number of points that can be placed in the $n \times n$ grid so that no three points lie on a line. Given a set $S$ of points in an Euclidean plane, the General Position Subset…

Combinatorics · Mathematics 2017-08-31 Paul Manuel , Sandi Klavžar

In this paper, connections between independent sets and the variety of mutual-visibility sets are studied. It is proved that every outer mutual-visibility set of a graph is independent if and only if the graph is distance edge-critical.…

Combinatorics · Mathematics 2026-03-02 Jing Tian , Csilla Bujtás , Sandi Klavžar

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

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

Let G(V,E) be a simple graph and let X subset of V. Two vertices u and v are said to be X-visible if there exists a shortest u,v-path P such that V(P) intersection X is a subset of {u, v}. A set X is called a mutual-visibility set of G if…

Combinatorics · Mathematics 2026-04-10 Tonny K B , Shikhi M

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

Let $G$ be a connected graph and $\cal X \subseteq V(G)$. By definition, two vertices $u$ and $v$ are $\cal X$-visible in $G$ if there exists a shortest $u,v$-path with all internal vertices being outside of the set $\cal X$. The largest…

Combinatorics · Mathematics 2024-03-26 Gülnaz Boruzanli Ekinci , Csilla Bujtás

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

A set of edges $X\subseteq E(G)$ of a graph $G$ is an edge general position set if no three edges from $X$ lie on a common shortest path. The edge general position number ${\rm gp}_{\rm e}(G)$ of $G$ is the cardinality of a largest edge…

Combinatorics · Mathematics 2023-10-17 Jing Tian , Sandi Klavžar , Elif Tan

The general position problem asks for large sets of vertices such that no three vertices of the set lie on a common shortest path. Recently a dynamic version of this problem was defined, called the \emph{mobile general position problem}, in…

The edge geodesic cover problem of a graph $G$ is to find a smallest number of geodesics that cover the edge set of $G$. The edge $k$-general position problem is introduced as the problem to find a largest set $S$ of edges of $G$ such that…

Combinatorics · Mathematics 2022-07-18 Paul Manuel , R. Prabha , Sandi Klavzar

Vertex similarity is a major problem in network science with a wide range of applications. In this work we provide novel perspectives on finding (dis)similar vertices within a network and across two networks with the same number of vertices…

Social and Information Networks · Computer Science 2013-05-28 Charalampos E. Tsourakakis

Networks are often modeled using graphs, and within this setting we introduce the notion of $k$-fault-tolerant mutual visibility. Informally, a set of vertices $X \subseteq V(G)$ in a graph $G$ is a $k$-fault-tolerant mutual-visibility set…

Combinatorics · Mathematics 2025-12-02 Serafino Cicerone , Gabriele Di Stefano , Sandi Klavžar , Gang Zhang

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

If $G$ is a graph and $X\subseteq V(G)$, then $X$ is a total mutual-visibility set if every pair of vertices $x$ and $y$ of $G$ admits a shortest $x,y$-path $P$ with $V(P) \cap X \subseteq \{x,y\}$. The cardinality of a largest total…

Combinatorics · Mathematics 2022-12-15 Jing Tian , Sandi Klavžar

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.