#7184: [with patch, needs review] Implement counting of spanning trees for
graphs
and digraphs
----------------------------+-----------------------------------------------
Reporter: AJonsson | Owner: rlm
Type: enhancement | Status: new
Priority: major | Milestone: sage-4.1.3
Component: graph theory | Keywords:
Work_issues: | Author:
Reviewer: | Merged:
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This patch allows us to count the number of spanning trees in a simple
graph, as well as the spanning out-trees from a user-defined root node in
a digraph.
Method used: Kirchhoff's matrix tree theorem [1] and the Laplacian matrix
for the simple graphs, and a variation of the same [2] in the directed
case.
[1] http://en.wikipedia.org/wiki/Kirchhoff%27s_theorem
[2] corollary 4.4 in
http://books.google.se/books?id=vbxdqhDKOSYC&printsec=frontcover&hl=en&source=gbs_navlinks_s
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7184>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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