The k-general d-position problem for graphs

TL;DR

This paper introduces the k-general d-position problem, extending the concept of general position in graphs, and provides bounds, exact values for specific graphs, and new labeling methods to analyze these sets.

Contribution

It generalizes the notion of general position to k-general d-position, develops bounds, and computes exact values for paths, cycles, and grids, introducing k-monotone-geodesic labeling.

Findings

Computed k-general d-position number for paths and cycles.

Established bounds based on subgraph properties.

Introduced k-monotone-geodesic labeling for grid analysis.

Abstract

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 $d$-position if no three vertices from the set lie on a common geodesic of length at most $d$. We generalize this notion further by defining a set of vertices to be in $k$-general $d$-position if no $k$ vertices of the set lie on a common geodesic of length at most $d$. The $k$-general $d$-position number of a graph is the largest cardinality of a $k$-general $d$-position set. We provide upper and lower bounds on the $k$-general $d$-position number of graphs in terms of the $k$-general $d$-position number of certain kinds of subgraphs. We compute the $k$-general $d$-position number of finite paths and cycles. Along the way we establish that the maximally even subsets of cycles, which were introduced in Clough and Douthett's work on music theory, provide the largest possible $k$-general $d$-position sets in $n$-cycles. We generalize Klav\v{z}ar and Manuel's notion of monotone-geodesic labeling to that of $k$-monotone-geodesic labeling in order to calculate the $k$-general $d$-position number of the infinite two-dimensional grid. We also prove a formula for the $k$-general $d$-position number of certain thin finite grids, providing a partial answer to a question asked by Klav\v{z}ar, Rall and Yero.