Skip to main content

Timeline for Genus of the graph $K_{4,2,2,2}$

Current License: CC BY-SA 3.0

18 events
when toggle format what by license comment
Apr 15, 2018 at 14:53 vote accept bor
Jan 28, 2018 at 17:51 answer added Timothy Sun timeline score: 14
Apr 13, 2017 at 12:19 history edited CommunityBot
replaced http://math.stackexchange.com/ with https://math.stackexchange.com/
Mar 28, 2014 at 7:15 comment added bor @j.c. I think the proof of Theorem 4.1 is not correct and the result is not correct.
Mar 27, 2014 at 13:52 comment added bor Thank you so much @j.c. . I will also try to understand the paper..
Mar 27, 2014 at 13:40 comment added j.c. @bor I find their proof of Theorem 4.1 very unclear. Here is a copy of their paper dl.dropboxusercontent.com/u/8101832/bettayebnguyen.pdf . And by the way, the paper cited by Felix Goldberg has a longer preprint version here preprint.math.uni-hamburg.de/public/papers/hbm/hbm2006251.pdf , the published article in particular refers to this version for more background
Mar 27, 2014 at 13:02 comment added bor @j.c. That a serious problem. Actually I don't have any access to this paper. Can you Figure what is the problem?
Mar 27, 2014 at 11:24 comment added j.c. If I'm not misreading, Theorem 4.1 from the reference given by David Wood states that the genus of the complete k-partite graph with partitions of sizes $V_1,V_2,\dots,V_k$ is $\sum_{i<j}\left\lceil\frac{(V_i-2)(V_j-2)}{4}\right\rceil+\left\lceil\frac{(k-3)(k-4)}{12}\right\rceil$, which gives zero for your graph. It also gives 1 for $K_{4,4,2}$ so I'm not sure what's going on.
Mar 27, 2014 at 10:37 comment added David Wood Here is a paper that seems relevant (based on the title): Said Bettayeb, Quan T. Nguyen, "The genus of the complete multipartite graph and the complete multi-layered graph," aiccsa, pp.1-4, ACS/IEEE International Conference on Computer Systems and Applications - AICCSA 2010, 2010. doi.ieeecomputersociety.org/10.1109/AICCSA.2010.5587024
Mar 27, 2014 at 10:14 comment added Felix Goldberg Since the answer is between $2$ and $4$, as shown by @DouglasZare, you might want to try the algebraic approach of Diestel and Bruhn (sciencedirect.com/science/article/pii/S0095895608000476). In fact, you might want to contact Henning Bruhn who might be able to compute this for you using their characterization!
Mar 27, 2014 at 9:14 comment added Douglas Zare One lower bound is the genus of $K_{4,4,2}$, which is $2$. An upper bound is the genus of $K_{10}$, which is $4$.
Mar 27, 2014 at 8:34 comment added bor @F.C. But that question has no answer. If that question has an answer, then it will be an answer to this question also.
Mar 27, 2014 at 8:14 comment added F. C. See question mathoverflow.net/questions/157894/genus-of-the-graph-k-m-2-2-2
Mar 27, 2014 at 7:11 comment added bor I have added...
Mar 27, 2014 at 7:10 history edited bor CC BY-SA 3.0
added 227 characters in body
Mar 27, 2014 at 6:25 comment added Tim Porter You could, perhaps, add a brief definition of this graph.
Mar 27, 2014 at 5:32 history edited bor CC BY-SA 3.0
added 3 characters in body
Mar 27, 2014 at 4:48 history asked bor CC BY-SA 3.0