TY  - JOUR
ID  - Staš2021
LB  - Staš2021
AU  - Staš, Michal
AU  - Valiska, Juraj
TI  - On the crossing numbers of join products of W<sub>4</sub>+P<sub>n</sub> and W<sub>4</sub>+C<sub>n</sub>
ST  - On the crossing numbers of join products of W<sub>4</sub>+P<sub>n</sub> and W<sub>4</sub>+C<sub>n</sub>
JO  - Opuscula Math.
JA  - Opuscula Math.
JF  - Opuscula Mathematica
PY  - 2021
VL  - 41
IS  - 1
SP  - 95
EP  - 112
DO  - https://doi.org/10.7494/OpMath.2021.41.1.95
UR  - https://doi.org/10.7494/OpMath.2021.41.1.95
AB  - The crossing number \(\mathrm{cr}(G)\) of a graph \(G\) is the minimum number of edge crossings over all drawings of \(G\) in the plane. The main aim of the paper is to give the crossing number of the join product \(W_4+P_n\) and \(W_4+C_n\) for the wheel \(W_4\) on five vertices, where \(P_n\) and \(C_n\) are the path and the cycle on \(n\) vertices, respectively. Yue et al. conjectured that the crossing number of \(W_m+C_n\) is equal to \(Z(m+1)Z(n)+(Z(m)-1) \big \lfloor \frac{n}{2} \big \rfloor + n+ \big\lceil\frac{m}{2}\big\rceil +2\), for all \(m,n \geq 3\), and where the Zarankiewicz's number \(Z(n)=\big \lfloor \frac{n}{2} \big \rfloor \big \lfloor \frac{n-1}{2} \big \rfloor\) is defined for \(n\geq 1\). Recently, this conjecture was proved for \(W_3+C_n\) by Klešč. We establish the validity of this conjecture for \(W_4+C_n\) and we also offer a new conjecture for the crossing number of the join product \(W_m+P_n\) for \(m\geq 3\) and \(n\geq 2\).
KW  - graph
KW  - crossing number
KW  - join product
KW  - cyclic permutation
KW  - path
KW  - cycle
SN  - 1232-9274
ER  -