TY - JOUR ID - Staš2020 LB - Staš2020 AU - Staš, Michal TI - On the crossing numbers of join products of five graphs of order six with the discrete graph ST - On the crossing numbers of join products of five graphs of order six with the discrete graph JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2020 VL - 40 IS - 3 SP - 383 EP - 397 DO - https://doi.org/10.7494/OpMath.2020.40.3.383 UR - https://doi.org/10.7494/OpMath.2020.40.3.383 AB - The main purpose of this article is broaden known results concerning crossing numbers for join of graphs of order six. We give the crossing number of the join product \(G^{\ast} + D_n\), where the disconnected graph \(G^{\ast}\) of order six consists of one isolated vertex and of one edge joining two nonadjacent vertices of the \(5\)-cycle. In our proof, the idea of cyclic permutations and their combinatorial properties will be used. Finally, by adding new edges to the graph \(G^{\ast}\), the crossing numbers of \(G_i+D_n\) for four other graphs \(G_i\) of order six will be also established. KW - graph KW - drawing KW - crossing number KW - join product KW - cyclic permutation SN - 1232-9274 ER -