Ben Pak Ching Li

E2-479 EITC
Department of Computer Science,
University of Manitoba,
Winnipeg, Manitoba, Canada   R3T 2N2
 

Welcome to my website.  I am an associate professor in the Department of Computer Science at the University of Manitoba, in Winnipeg, Manitoba, Canada.  My research activities are focused in  combinatorial designs and algorithms. 

Teaching

I will be teaching the following courses in the upcoming year (2009-2010).

  1. Programming Practices (COMP2160)
  2. Introduction to Computer Systems (COMP2280)

Research

My research interests lie in two areas:

  1. Combinatorial Designs, and
  2. Algorithms.

Combinatorial Designs

The types of combinatorial designs that I am most interested in are balanced incomplete block designs, covering designs, Lotto designs, Latin squares, hash families and cover-free families.  I study designs from two different aspects: theoretical and algorithmic. 

Link to my Lotto tables.
Link to files containing all non-isomorphic restricted Savate-Beam triple systems of order 6.
Link to files containing all non-isomorphic Savate-Beam triple systems of order 6.

Algorithms

I am interested in the complexity of problems (NP-Completeness) and approximation algorithms for NP-Hard problems. 

Some Recent Publications

D. Deng, D.R. Stinson, P.C. Li, G.H.J. van Rees, R. Wei. Constructions and Bounds for (m,3)-Splitting Systems. Discrete Mathematics, 307(2007), 18-37. 

R.T. Bilous, C.W.H. Lam, L.H. Thiel, P.C. Li, G.H.J. van Rees,S.P. Radziszowski, W.H. Holzmann, H. Kharaghani. There is no (22,8,4) Block Design.  Journal of Combinatorial Designs.  Published online October 7, 2006.

P.C.Li, G.H.J. van Rees, R. Wei, Constructions of 2-Cover-Free Families and Related Separating Hash Families. Journal of Combinatorial Designs, 14(2006), 423-440.

P.C. Li, M. Toulouse, Variations of the Maximum Leaf Spanning Tree Problem for Bipartite Graphs. Information Processing Letters, 97(2006),129-132.

M. Greig, P.C. Li & G.H.J. van Rees. Covering Designs on 13 Blocks. Utilitas Math. 70(2006) 221-261.

P.C. Li & M. Toulouse. Some NP-Completeness Results on Partial Steiner Triple Systems and Parallel Classes. Ars Combinatorica 80(2006) 45-51.

C. Dai, P.C. Li, M. Toulouse, A Cooperative Multilevel Tabu Search Algorithm for the Covering Design Problem. LNCS 3871(2006), 119-130. 

(Ben) Pak Ching Li and G.H. John van Rees.  Lotto Designs (pages 529-536) in The CRC Handbook of Combinatorial Designs, 2nd Edition(2006)

P.C. Li, D.R. Stinson, G.H.J. van Rees and R. Wei. On {123,124,134}-free Systems. Congressus Numerantium , V183 (2006) 161-174.

W.L.Kocay, P.C. Li, On 3-Hypergraphs with Equal Degree Sequences. Ars Combinatorica, 82(2007) 145-157.

P.C. Li, M. Toulouse. Maximum Leaf Spanning Trees for Grid Graphs. (Accepted to appear in JCMCC) [Dec. 21, 2006].

P.C. Li., G.H.J. van Rees.  Mutually Nearly Orthogonal Latin Squares. Journal of Combinatorial Mathematics and Combinatorial Computing, V62 (2007) 13-24.

C. Dai, B. Li, M. Toulouse, A  Multilevel Cooperative Tabu Search Algorithm for the Covering Design Problem. Journal of Combinatorial Mathematics and Combinatorial Computing, V68 (2009) 33-66.

M.S. Keranen, W.H. Kocay and B. Li, Degree sequence conditions for partial Steiner triple systems. (Accepted to appear in the Bulletin of the ICA) [April 16, 2008].

Contact Information

phone: (204) 474-8834
fax: (204) 474-7609
email: lipakc AT cs DOT umanitoba DOT ca