Treewidth 2 in the Planar Graph Product Structure Theorem
We prove that every planar graph is contained in $H_1\boxtimes H_2\boxtimes K_2$ for some graphs $H_1$ and $H_2$ both with treewidth 2. This resolves a question of Liu, Norin and Wood [arXiv:2410.20333]. We also show this result is best possible: for any $c \in \mathbb{N}$, there is a planar graph $...
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          | Published in | Discrete Mathematics and Theoretical Computer Science Vol. 27:2; no. Graph Theory; p. 1 | 
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| Main Authors | , , , , | 
| Format | Journal Article | 
| Language | English | 
| Published | 
            DMTCS
    
        01.08.2025
     Discrete Mathematics & Theoretical Computer Science  | 
| Subjects | |
| Online Access | Get full text | 
| ISSN | 1365-8050 1462-7264 1365-8050  | 
| DOI | 10.46298/dmtcs.14785 | 
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| Summary: | We prove that every planar graph is contained in $H_1\boxtimes H_2\boxtimes K_2$ for some graphs $H_1$ and $H_2$ both with treewidth 2. This resolves a question of Liu, Norin and Wood [arXiv:2410.20333]. We also show this result is best possible: for any $c \in \mathbb{N}$, there is a planar graph $G$ such that for any tree $T$ and graph $H$ with $\text{tw}(H) \leqslant 2$, $G$ is not contained in $H \boxtimes T \boxtimes K_c$.
Comment: arXiv admin note: text overlap with arXiv:2410.20333 | 
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| ISSN: | 1365-8050 1462-7264 1365-8050  | 
| DOI: | 10.46298/dmtcs.14785 |