RT journal article T1 Lower General Position Sets in Graphs A1 Di Stefano, Gabriele A1 Klavžar, Sandi A1 Krishnakumar, Aditi A1 Tuite, James A1 González Yero, Ismael A2 Matemáticas K1 computational complexity K1 general position number K1 geodetic number K1 Kneser graphs K1 line graphs K1 universal line AB A subset S of vertices of a graph G is a 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 lower general position number gp−(G) of G, which is the number of vertices in a smallest maximal general position set of G. We show that gp−(G) = 2 if and only if G contains a universal line and determine this number for several classes of graphs, including Kneser graphs K(n, 2), line graphs of complete graphs, and Cartesian and direct products of two complete graphs. We also prove several realisation results involving the lower general position number, the general position number and the geodetic number, and compare it with the lower version of the monophonic position number. We provide a sharp upper bound on the size of graphs with given lower general position number. Finally we demonstrate that the decision version of the lower general position problem is NP-complete. PB University of Zielona Gora SN 2083-5892 YR 2025 FD 2025 LK http://hdl.handle.net/10498/38042 UL http://hdl.handle.net/10498/38042 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 10-may-2026