Timeline for Is there is a constant $c$ such that toroidal graphs are minor-$c$-colorable?
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Sep 24, 2023 at 1:34 | comment | added | bof | Toroidal graphs (and their minors, which are also toroidal) are $7$-colorable, as was shown by Heawood in 1890. en.wikipedia.org/wiki/Heawood_conjecture | |
| Sep 22, 2023 at 5:03 | comment | added | bof | I don't understand. Isn't a minor of a toroidal graph also toroidal? So how is "toroidal graphs are minor-$c$-colorable" different from "toroidal graphs are $c$-colorable"? And aren't toroidal graphs $7$-colorable? And by the way, how is it "clearly" that planar graphs are minor-$4$-colorable?? | |
| Sep 22, 2023 at 3:23 | history | asked | Xin Zhang | CC BY-SA 4.0 |