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A Bijective Proof of a Theorem of Knuth

Published online by Cambridge University Press:  21 July 2010

HODA BIDKHORI  and
SHAUNAK KISHORE
HODA BIDKHORI
Affiliation:
Massachusetts Institute of Technology, Massachusetts Avenue, Cambridge, MA 02139, USA (e-mail: bidkhori@mit.edu, skishore@mit.edu)
SHAUNAK KISHORE
Affiliation:
Massachusetts Institute of Technology, Massachusetts Avenue, Cambridge, MA 02139, USA (e-mail: bidkhori@mit.edu, skishore@mit.edu)
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Abstract

The line graph G of a directed graph G has a vertex for every edge of G and an edge for every path of length 2 in G. In 1967, Knuth used the Matrix Tree Theorem to prove a formula for the number of spanning trees of G, and he asked for a bijective proof [6]. In this paper, we give a bijective proof of Knuth's formula. As a result of this proof, we find a bijection between binary de Bruijn sequences of degree n and binary sequences of length 2n−1. Finally, we determine the critical groups of all the Kautz graphs and de Bruijn graphs, generalizing a result of Levine [7].

Type
Paper
Information
Combinatorics, Probability and Computing , Volume 20 , Issue 1 , January 2011 , pp. 11 - 25
Copyright
Copyright © Cambridge University Press 2010

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References

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