The Hong Kong University of Science and Technology Department of Computer Science PhD Thesis Defence "Counting the number of spanning trees in special graphs" By Mr. Yuanping Zhang Abstract The number of spanning trees in a (di-)graph (network) is an important, well-studied quantity, both for application reasons as well as being of separate combinatorial interest. Most research in this area is devoted to determining exact formulae for the number of spanning trees in particular classes of special graphs. In this thesis, we start by describing known general methods for counting the number of spanning trees in (di-) graphs. We then discuss our new results: we start by showing that the number of spanning trees in the circulant graph Cns1,s2,K, sk always satisfies a recurrence relation in n and describe how to derive this relation. The asymptotic behavior of these quantities is also derived. We then extend results due to Boesch and Prodinger to derive closed formulae for the number of spanning trees in circulant graphs and graphs related to circulant graphs in terms of Chebyshev polynomials. We conclude by describing a method of counting the number of spanning trees in one class of double fixed-step loop networks. Date: Friday, 2 August 2002 Time: 2:00p.m.-4:00p.m. Venue: Room 2302 Lifts 17-18 Chairman: Dr. Kin-Yin Li (MATH) Committee Members: Dr. Mordecai Golin (Supervisor) Dr. Sunil Arya Prof. William Steiger Dr. Beifang Chen (MATH) Prof. Helmut Prodinger (Mathematics, Wits Univ.) **** ALL are Welcome ****