Results in Mathematics ( IF 2.2 ) Pub Date : 2021-05-26 , DOI: 10.1007/s00025-021-01438-x Sandi Klavžar , Balázs Patkós , Gregor Rus , Ismael G. Yero
The general position number \(\mathrm{gp}(G)\) 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 general position number of cylinders \(P_r\,\square \,C_s\) is deduced. It is proved that \(\mathrm{gp}(C_r\,\square \,C_s)\in \{6,7\}\) whenever \(r\ge s \ge 3\), \(s\ne 4\), and \(r\ge 6\). A probabilistic lower bound on the general position number of Cartesian graph powers is achieved. Along the way a formula for the number of gp-sets in \(P_r\,\square \,P_s\), where \(r,s\ge 2\), is also determined.
中文翻译:
笛卡尔积中的一般位置集
连通图G的总位置数\(\ mathrm {gp}(G)\)是最大顶点集S的基数,因此从S出发,没有三个不同的顶点位于同一个测地线上。这样的集合称为G的gp集。推导出圆柱体的一般位置数\(P_r \,\ square \,C_s \)。证明\(\ mathrm {gp}(C_r \,\ square \,C_s)\ in \ {6,7 \} \)每当\(r \ ge s \ ge 3 \),\(s \ ne 4 \)和\(r \ ge 6 \)。实现了笛卡尔图幂的一般位置数的概率下界。一路走来的gp集数量的公式\(P_r \,\ square \,P_s \),其中\(r,s \ ge 2 \)也是确定的。