Timeline for Generalizations of the four-color theorem
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Mar 8, 2021 at 9:59 | comment | added | P.Labarque | @GilKalai, an answer to your question can be found in : math.stackexchange.com/questions/2490702/lattice-point-geometry and if the three vertices of a triangle must be on different parity-lattice points then they have three different colours folowing the picture. | |
| Mar 6, 2021 at 20:55 | comment | added | Gil Kalai | @P.Labarque, I added the picture. Can you explain why a xx.5 triangle must involve 3 different colours? | |
| Mar 2, 2021 at 20:35 | review | Low quality posts | |||
| Mar 3, 2021 at 7:22 | |||||
| Mar 2, 2021 at 20:31 | history | edited | Gil Kalai | CC BY-SA 4.0 |
added 122 characters in body
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| Feb 28, 2021 at 18:57 | comment | added | András Bátkai | Is this a generalization? | |
| Feb 28, 2021 at 18:49 | comment | added | P.Labarque | Pick's Theorem can be used here to calulate the areas. | |
| Feb 28, 2021 at 17:14 | comment | added | P.Labarque | In a Maximal Planar Graph all faces are triangles, also the infinite face. 4-colouring the vertices of such a graph is equivalent to 4colouring cubic maps (they are duals). "I was not allowed" to include the image in the original post, if anyone can do it please don't hesitate. | |
| Feb 28, 2021 at 15:56 | comment | added | Will Sawin | You should be able to edit this answer so that the image is included in it, rather than post it in a separate answer, which would make things clearer. It would also be helpful to add some more details: What is an MPG? What exactly is the relationship of this to the four-color theorem? Your argument seems to suggest it is a weakening, not a strengthening. | |
| Feb 28, 2021 at 15:29 | comment | added | P.Labarque | Give the vertices on the grid crossings folowing colours: odd-odd=1, odd-even=2, even-odd=3 and even-even=4. | |
| Feb 28, 2021 at 15:07 | comment | added | Gil Kalai | Can you please elaborate? | |
| Feb 28, 2021 at 14:33 | review | Low quality posts | |||
| Feb 28, 2021 at 20:05 | |||||
| Feb 28, 2021 at 14:11 | review | Late answers | |||
| Feb 28, 2021 at 14:33 | |||||
| Feb 28, 2021 at 14:01 | review | First posts | |||
| Feb 28, 2021 at 16:01 | |||||
| S Feb 28, 2021 at 13:54 | history | answered | P.Labarque | CC BY-SA 4.0 | |
| S Feb 28, 2021 at 13:54 | history | made wiki | Post Made Community Wiki by P.Labarque |