Updated: April 12, 2007

Combinatorics Seminar

California Institute of Technology
Thursdays at 11:30 am, Sloan, room 159
Please check the Caltech Calendar and
See Peter Keevash's page for updates on links to ABSTRACTS


Thursday, April 12, 2007
Cheng Yeaw Ku (Caltech)
Title: Non-trivial Intersecting Families
12 noon // 159 Sloan

Thursdays, Sloan, room 159

upcoming seminars:

Thursday, April 19, 2007
Peter Keevash (Caltech)
Title: Set systems without a simplex or a cluster
12 noon // 159 Sloan

Thursday, April 26, 2007
Paul Renteln (Cal State, San Bernardino)
Title: On the Spectrum of the Derangement Graph
12 noon // 159 Sloan

Recent lectures were: Thursday, April 5, 2007
Mirjana Vuletic (Caltech)
Title: A generalization of MacMahon's formula
12 noon // 159 Sloan

Thursday, March 29, 2007
Daniel Katz (Princeton)
Title: Polynomial Equations Modulo Prime Powers
12 noon // 159 Sloan

Thursday, January 11, 2007
Sebastian Cioaba (UC San Diego)
Title: Covering hypergraphs with cuts
11:30 a.m. // 159 Sloan

Thursday, October 12, 2006
Speaker: Cheng Yeaw Ku (Caltech)
"Intersecting families in the alternating group and direct product of symmetric groups"

Thursday, March 9, 2006
Yi Zhao (Georgia State)
Title: Traces of finite sets

Thursday, March 30, 2006
Leonid Gurvits (Los Alamos National Laboratory)
Title: Hyperbolic polynomials and Van der Waerden / Schrijver-Valiant like conjectures

Thursday, February 23, 2006
Peter Keevash (Caltech)
Title: Algebraic techniques for Turán problems

Thursday, February 16, 2006
Cheng Yeaw Ku (Caltech) Thursday, February 9, 2006 Title: Channel Assignments for Infinite Graphs

Thursday, January 26, 2006
Eric Sundberg (Whittier College)
Title: An Introduction to Positional Game Theory

Thursday, January 19, 2006
Bahattin Yildiz (Caltech)
Title: Homogeneous Weights modulo prime powers of Linear Codes over Galois Rings

Thursday, January 12, 2006
Po-Shen Loh (Princeton)
Title: Independent transversals in locally sparse graphs

Thursday, December 8, 2005
Richard Anstee (UBC)
TITLE: Forbidden Configurations: An update

Tuesday, December 6, 2005
Pawel Wocjan (Caltech)
TITLE: Mutually Unbiased Bases and Semi-regular Relative Difference Sets in Abelian Groups

Thursday, December 1, 2005
Xiaoyu Liu (Caltech)
Divisible code bound

Thursday, November 10, 2005
Steven Butler (UCSD)
On permutations which avoid the patterns 1324 and 2143

Thursday, November 9, 2005
Steven Butler (UCSD)
"On permutations which avoid the patterns 1324 and 2143"
See Abstract

Thursday, October 27, 2005
Peter Keevash (Caltech)
"Report on a recent combinatorial meeting"

Cheng Ku (Caltech)
Lecture Two

Thursday, October 13, 2005
Cheng Ku (Caltech)
Lecture One

Thursday, September 29, 2005
Richard Wilson (Caltech)
"An Ax-Katz-type theorem for systems of congruences"

Thursday, June 9, 2005
Dan Pragel (Caltech)
Central Digraphs, Central Groupoids and Zero-One Matrices A such that A^2 = J.
See Abstract

Thursday, June 2, 2005
Peter Keevash (Caltech)
Pairwise intersections and forbidden configurations
See Abstract

May 26, 2005
Yuval Roichman ((Bar-Ilan)
Statistics on permutation groups, canonical words and pattern avoidance
See Abstract

Thursday, May 19, 2005
Paul Zinn-Justin (Paris-Sud)
Towards a proof of the Razumov--Stroganov conjecture?
See Abstract

Thursday, May 12, 2005
Terence Tao (UCLA)
The determinant and singularity probability of a random ± 1 matrix

See Abstract

Thursday, May 5, 2005
Allen Knutson (UC Berkely)
The glue between Young tableaux
See Abstract

Thursday, April 21, 2005
Richard Wilson (Caltech)
Revisiting the (t, k)-subset inclusion matrices
See Abstract

Thursday, April 14
Benny Sudakov (Princeton University)
Max Cut - combinatorial perspective
See Abstract

THURSDAY, March 3, 2005
Dhruv Mubayi (University of Illinois)
New developments on Ramsey-Turan theory for hypergraphs
See Abstract

Peter Dukes (University of Victoria)
The cycle structure of uniform one-factorizations from starters in finite fields
See see details of his visit

Carlos Salazar-Lazaro (Caltech)
Progress on the existence problem of Skew Hadamard Difference Sets
See Abstract

Pawel Wocjan (Calech)
Limitations of nice mutually unbiased bases
See Abstract

Pawel Wocjan (Calech)
Eulerian orthogonal arrays
See Abstract

November 10
Noam Berger (Caltech)
Mixing time for the biased card shuffling and the asymmetric exclusion process

October 28
Peter Keevash (Caltech)
Multicoloured extremal problems
See Abstract

October 21
Pawel Wocjan, Caltech
New construction of mutually unbiased bases in square dimensions
See Abstract

October 14
Richard Wilson (Caltech)
Incidence matrices and a zero-sum Ramsey-type problem

October 7
Peter Keevash (Caltech)
The role of approximate structure in extremal combinatorics
See Abstract

September 30
Daniel J. Katz (Caltech)
A theorem of N. Katz from a generalization McEliece’s Theorem
see photo

April 15
Rick Wilson (Caltech)
Decompositions of edge-colored complete graphs

March 18
Heeralal Janwa (University of Puerto Rico)
New Explicit Families of Constant Degree Expander Graphs: Their Tanner Codes and Decoding

March 11
Yukiyasu Mutoh (Keio University, Yokohama, Japan)
Decompositions of a complete graph into colorwise simple graphs.

March 4
Sergey Kitaev (U. of Kentucky)
Numerical characteristics of unavoidable sets

February 26
Richard Wilson (Caltech)
Reed-Muller codes and the Ax-Katz theorem

Photo by Tania Parsa, at IPM, Tehran, 2003.

Rick Wilson has hosted the combinatorics seminar at Caltech for 23 years.


Recent visitor was Qing Xiang from the University of Delaware.

Qing presented his first lecture Thursday, January 15, 2004
The invariant factors of the incidence matrices of points and subspaces in PG(n,q) and AG(n,q)
See some of Qing's notes on this lecture
His second lecture was presented Thursday, January 29, 2004
On Mathon's construction of maximal arcs in Desarguesian planes
See some of Qing's notes at this lecture

Click below for a sampling of seminar speakers and their visits:

  • Qing Xiang, University of Delaware (January 5-February 4, 2004)
  • Shahriar Shahriari, Pomona College, Claremont (December 28,2003)
  • Chris Godsil, University of Waterloo (September 8, 2003)
  • Doug Leonard, Auburn University (July, 2003)