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arXiv · 2609.02283

The game chromatic number of generalized Mycielski graphs of paths and cycles

Yushuang Mou·Qiang Sun·Chao Zhang
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Abstract

The graph coloring game is a two-player game in which the players alternately color an uncolored vertex of a graph $G$. The game chromatic number is the minimum number of colors needed for the first player to guarantee a win. We investigate this parameter for generalized Mycielski graphs $M_k(G)$, where $G$ is a path $P_n$ or a cycle $C_n$ with $n$ vertices. For every $k\geq2$ and $n\geq5$, we establish $4\leq\chi_g\bigl(M_k(P_n)\bigr)\leq5$ and $4\leq\chi_g\bigl(M_k(C_n)\bigr)\leq5$. We also determine the exact values $\chi_g\bigl(M_2(P_5)\bigr)=\chi_g\bigl(M_2(P_6)\bigr)=4$. The proofs of the lower bounds use a configuration in which Bob can create two threats simultaneously, while the four-color upper bounds in the two exact cases are proved using the double-doctor lemma. Thus the number of layers and the order of the base graph may grow, but the game chromatic number remains bounded by five.

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Yushuang Mou, Qiang Sun, Chao Zhang. 2026-09-02. The game chromatic number of generalized Mycielski graphs of paths and cycles. https://arxiv.org/abs/2609.02283

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