Jernej
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Registered User
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Undergrad student interested in extremal aspects of combinatorics/graph theory and theoretical computer science.
If you happen to have a neat exercise problem, feel free to post it at http://exwiki.org
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Apr 26 |
awarded | ● Nice Question |
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Mar 19 |
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Good papers/books/essays about the thought process behind mathematical research There is also a 41mins long talk by Hamming youtube.com/watch?v=a1zDuOPkMSw if you don't like to read the transcript. |
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Mar 14 |
awarded | ● Notable Question |
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Mar 12 |
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Applications of line graphs Delio, can you cite one of these sociological papers? |
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Mar 7 |
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Applications of line graphs Just a suggestion. Find a suitable interpretation of vertex/edge colorings. And then play with the fact that the chromatic index of a graph is the chromatic number of its line graph. |
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Feb 17 |
awarded | ● Nice Question |
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Feb 17 |
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Minimal graphs with a prescribed number of spanning trees The $x$-axis represents $n$ while the $y$ axis represents $\alpha(n)$ |
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Feb 11 |
awarded | ● Organizer |
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Feb 11 |
revised |
determinant of fibonacci-sum graphs edited tags |
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Feb 11 |
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determinant of fibonacci-sum graphs The diagonal is of course zero since I am first constructing a graph and then computing the adjacency matrix. |
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Feb 11 |
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determinant of fibonacci-sum graphs I always get zero with the following sage program for constructing the graph pastebin.com/0t9GHHzM |
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Feb 9 |
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Mclaughlin Graph When I try to run the first example in gap it stops with this error in the first line - Variable: 'AtlasGenerators' must have a value. Do you happen to see why? |
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Feb 7 |
awarded | ● Popular Question |
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Feb 7 |
revised |
Spanning trees in planar graphs deleted 366 characters in body; deleted 16 characters in body |
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Feb 7 |
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Spanning trees in planar graphs Weird. I'll try to run the program again and see why the proposed graph is not found. It clearly looks like a counterexample to the stated answer! |
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Feb 4 |
awarded | ● Nice Question |
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Feb 2 |
awarded | ● Yearling |
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Feb 2 |
awarded | ● Yearling |
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Feb 1 |
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Is the empty graph a tree? @Günter Rote Sage simply computes the subdivision of the Laplacian matrix and its determinant. |
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Feb 1 |
asked | Is the empty graph a tree? |
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Jan 17 |
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Hamiltonian cycles in power-graphs That's a very nice question! I have tested the conjecture for values of $n$ up to 500 and it holds. |
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Jan 17 |
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Generating non-isomorphic graphs by adding edges to a given graph @BrendanMcKay the base graph has an automorphism group of order 2^85 * 3^32 * 5^16 * 7^16 |
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Jan 16 |
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Generating non-isomorphic graphs by adding edges to a given graph @GerhardPaseman A and B are indeed disjoint. And there are no edges between! I don't see any reasons why such a matching would not exists since $B$ is larger then $A.$ Yes, all I really want are nonisomorphic extensions that match $A$ to $B$. BTW, may I ask you about system designs? |
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Jan 16 |
revised |
Generating non-isomorphic graphs by adding edges to a given graph edited body |
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Jan 16 |
asked | Generating non-isomorphic graphs by adding edges to a given graph |
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Jan 16 |
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Spanning trees in planar graphs @utdiscant In case you haven't noticed the conjecture does not hold! |
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Jan 2 |
awarded | ● Popular Question |
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Dec 20 |
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Similarity measure between 2 bi-partite graph. I suggest you ask this sort of questions on cs.stackexchange.com. As for your question you could use some hybrid function based on the generalized degree sequence of a weighted graph + graph isomorphism + wiener index. But it is hard to give you good suggestions without knowing the full requirements. |
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Dec 20 |
asked | Structure of almost all bipartite graphs |
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Dec 20 |
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Similarity measure between 2 bi-partite graph. I know its irritating but your question is still not well defined. What should the measure say if two graphs have no pair of such vertices but there is some pair where the weights are very close? As such the question is not well defined. |
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Dec 20 |
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Similarity measure between 2 bi-partite graph. And what exactly should this measure resemble? In what way do you define graph similarity? |
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Dec 20 |
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Similarity measure between 2 bi-partite graph. It would help if you could specify some additional criterion for your measure. otherwise you could just check for graph isomorphism. |
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Dec 15 |
answered | Spanning trees in planar graphs |
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Dec 15 |
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Counting spanning trees when blowing up vertices Here are the next few values of the number of spanning trees for blowup graphs obtained by taking $K_4$ as a start $$16, 6000, 113906250000, 280568536600470542907714843750000$$ let me know if you want some other values relative to other starting graphs. As for the main question,try to express the adjacency matrix of the blowup graph and see if you can find its eigenvalues in terms of $K_3$ and the base graph. |
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Dec 15 |
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Counting spanning trees when blowing up vertices What exactly is the adjacency among the triangles? If $T_u,T_v$ are triangles that were obtained from two adjacent vertices $u,v$ then every vertex of $T_v$ is adjacent to every vertex of $T_u$? |
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Dec 15 |
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Counting spanning trees when blowing up vertices So what you really want is derive an identity for the spectrum of the truncated graph with relation to the spectrum of the original graph. By spectrum I mean the eigenvalues of the adjacency or Laplacian matrix. In this case it does not matter. |
