Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Standard Time
901 Van Vleck (or Online)
Fall 2024 Schedule

To subscribe to the email list, email
combsem+subscribe@g-groups.wisc.edu

September
9 (on-line) Paul Terwilliger
The nucleus of a Q-polynomial distance-regular graph 16 (on-line) Mojtaba Jazaeri (Shahid Chamran University of Ahvaz)
On Q-polynomial distance-regular graphs with a linear dependency involving a 3-clique 23 (on-line) Bill Martin (WPI)
Galois fusions of association schemes 30 (on-line) Kimberly Jane Harry (UW Milwaukee)
A product of Fibonacci and a power of q
October
7 (on-line) Sebastian Cioaba (U. Delaware)
Some open problems in spectral graph theory 14 (on-line) Daniel Gromada (Czech Technical University in Prague)
Quantum association schemes 21 (on-line) Vidas Regelskis (U. Hertfordshire)
What is a Yangian? 28 (on-line) Ian Seong
Projective geometries, Grassmann graphs, and generalized Askey-Wilson relations
November
4 (on-line) Daniel Hawtin (U. Rijeka, Croatia)
Group actions on codes in graphs 11 (on-line) John Byrne (U. Delaware)
A general theorem in spectral extremal graph theory 18 (on-line) Hermie Monterde (U. Manitoba)
Perfect s-pair state transfer in distance-regular graphs 25 (on-line) Safet Penjic (U. Primorska)
On (di)graphs, doubly stochastic matrices, and commutative association schemes
December
2 (on-line) Nathaniel Benjamin (Dordt U.)
Association schemes obtained from the action of the general unitary group on isotropic vectors 9 (on-line) Bart De Bruyn (U. Ghent)
Divisible design graphs from symplectic graphs

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Standard Time
901 Van Vleck (or Online)
Spring 2024 Schedule

To subscribe to the email list, email combsem+subscribe@g-groups.wisc.edu

January
29 (on-line) Luc Vinet (U. Montreal)
Entanglement of free-fermion systems, signal processing and algebraic combinatorics
February
5 (on-line) Allen Herman (U. Regina)
Polynomial association schemes: a survey of recent developments 12 (on-line) Bill Martin (WPI)
Unfinished business in the Q-polynomial world 19 (on-line) Benjamin Young
General and planar #CSP equality corresponds to classical and quantum isomorphism 26 (on-line) Tomasz Przezdziecki (U. Edinburgh)
Drinfeld rational fractions for affine Kac-Moody quantum symmetric pairs
March
4 (on-line) Alena Ernst (U. Paderborn)
Designs in finite general linear groups 11 (on-line) Milen Yakimov (Northeastern U)
Reflective centres of module categories and quantum K-matrices 18 (on-line) Sarah Post (U. Hawaii)
Recent progress on the higher rank Racah Algebra 25 Spring Recess
April
1 (on-line) Xiaohong Zhang (U. Montreal)
Signed or oriented Cayley graphs with nice spectrum 8 (on-line) John Caughman (Portland State U.)
Bipartite rank and density of generalized Johnson graphs 15 (on-line) Jimmy Vineyard
A 3-dimensional generalization of Pascal's triangle and its connection to Leonard pairs 22 (on-line) Giusy Monzillo (U. Primorska)
On the Q-polynomial property of the full bipartite graph of the Hamming graph 29 (on-line) Charles Brittenham (Colgate U.)
Random walks and the "Euclidean" association scheme in finite vector spaces

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Standard Time
901 Van Vleck (or Online)
Fall 2023 Schedule

To subscribe to the email list, email combsem+subscribe@g-groups.wisc.edu

September
11 (on-line) Paul Terwilliger
Spin models and distance-regular graphs of q-Racah type 18 (on-line) Paul Terwilliger
Generalizing the Q-polynomial property to graphs that are not distance-regular 25 (on-line) Stefko Miklavic (U. Primorska)
Graphs that support a uniform structure
October
2 (on-line) Venkata Raghu Tej Pantangi (U. Regina)
How strong are Erdos-Ko-Rado type results? 9 (on-line) Taiyo Terada (Portland State U.)
Leonard pairs and the proof of the Kresch-Tamvakis Conjecture 16 (on-line) Nicolas Crampe (U. Tours, France)
Factorized Leonard pairs 23 (on-line) Hanmeng (Harmony) Zhan (WPI)
On the second largest eigenvalue of a tree 30 (on-line) Bangteng Xu (East Kentucky U.)
Association schemes and partial geometric designs
November
6 (on-line) Blas Fernandez
2-Y-homogeneous distance-biregular graphs: State of the art and beyond 13 (on-line) Krystal Guo (U. Amsterdam)
Bounding the fractional chromatic number with eigenvalues using symmetry 20 (on-line) Sabrina Lato (U. Waterloo)
Distance-biregular graphs and the Q-polynomial property 27 (on-line) Safet Penjic (U. Primorska)
Combinatorial structure and algebraic characterizations of distance-regular digraphs
December
4 (on-line) Sarobidy Razafimahatratra (U. Primorska)
The ratio bound and the Erdos-Ko-Rado theorem for transitive groups 11 (on-line) Sarah Bockting-Conrad (DePaul U.)
The b-chromatic number of rooted product graphs

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Standard Time
901 Van Vleck (or Online)
Spring 2023 Schedule

To subscribe to the email list, email combsem+subscribe@g-groups.wisc.edu

January
30 (on-line) Daniel Gromada (Czech Technical University in Prague)
Quantum symmetries of graphs
February
6 (on-line) Aleksandra Sobieska
Taylor resolutions over complete intersections 13 (on-line) Jan Kretschmann (U. Wisconsin-Milwaukee)
Counting parking sequences and parking assortments through permutations 20 (on-line) Weinan Zhang (U. Virginia)
Drinfeld type presentations for affine i-quantum groups 27 (on-line) Ferdinand Ihringer (Ghent U.)
Some switching from strongly regular graphs
March
6 (on-line) Jonas Hartwig (Iowa State U.)
The diagonal reduction algebra of the Lie superalgebra osp(1|2) 13 Spring Recess
20 (on-line) Rodrigo Pimenta (U. Manitoba)
A new family of free (para)fermions 27 (on-line) Meri Zaimi (U. Montreal)
Bivariate P-polynomial association schemes
April
3 (on-line) Yaolong Shen (U. Virginia)
Quasi-parabolic Kazhdan-Lusztig bases and i-Schur duality 10 (on-line) Chia-Yi Wen (National Yang Ming Chiao Tung U. Taiwan)
A connection behind the Terwilliger algebras of the hypercube and its halved graph. 17 (on-line) Roghayeh Maleki (U. Primorska)
The cyclotomic eigenvalue question for commutative association schemes 24 (on-line) Guillaume Lemarthe (U. Tours)
Fused K-operators and the q-Onsager algebra
May
1 (on-line) Ian Seong
On a characterization of the Grassmann graphs 8 (on-line) Owen Goff
The Drinfeld presentation for the q-Onsager algebra

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Standard Time
901 Van Vleck (or Online)
Fall 2022 Schedule

To subscribe to the email list, email combsem+subscribe@g-groups.wisc.edu

September
12 (on-line) Paul Terwilliger
Tridiagonal pairs, alternating elements, and distance-regular graphs 19 (on-line) Himanshu Gupta (U. Delaware)
The least Euclidean distortion constant of a distance-regular graph 26 (on-line) Jose Rodriguez
Solving sparse polynomial systems
October
3 (on-line) Keru Zhou
q-Fractional Askey-Wilson integrals and related semigroups of operators 10 (on-line) Rebecca Patrias (U. Saint Thomas)
A web basis of invariant polynomials from noncrossing partitions 17 (on-line) Jae-ho Lee (U. North Florida)
Circular Hessenberg pairs 24 (on-line) Ian Seong
A q-analog of the adjacency matrix of the n-cube 31 (on-line) Allen Herman (U. Regina)
Association schemes and polytopes
November
7 (on-line) Blas Fernandez (U. Primorska)
On (almost) 2-Y-Homogeneous distance-biregular graphs 14 (on-line) Stefko Miklavic (U. Primorska)
The Terwilliger algebra of a (not necessarily distance-regular) graph 21 (on-line) Erika Pirnes
Minimal relations for the balanced algebra 28 (on-line) Nathan Nicholson
The Terwilliger algebra of a 2-homogeneous bipartite distance-regular graph
December
5 (on-line) Peter Ruan
A uniform approach to the Damiani, Beck, and alternating PBW bases for U^+_q 12 (on-line) Ada Chan (York U.)
Quantum isomorphism and Hadamard graphs

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm Central Daylight Time
901 Van Vleck (or Online)
Spring 2022 Schedule

To subscribe to the email list, email combsem+subscribe@g-groups.wisc.edu

January
31 Paul Terwilliger
Compatibility and companions for Leonard pairs
February
7 Peter Ruan
Some elements in the quantum affine sl2 algebra 14 Mike Zabrocki (York U.)
Plethysm and the algebra of uniform block permutations 21 Owen Goff
The q-Onsager algebra and the quantum plane 28 Radhakrishnan Balu
Topological quantum structures from association schemes
March
7 Ian Seong
Using a Grassmann graph to recover the underlying projective geometry 14 Spring Recess
21 Bohdan Kivva (U. Chicago)
New characterizations of Johnson and Hamming graphs. Babai's motion conjecture 28 Pierre-Antoine Bernard (CRM, U. Montreal)
The Terwilliger algebra and the entanglement of free fermions on graphs
April
4 Vadim Gorin
Addition of matrices at high and low temperatures 11 Nathan Nicholson
The generalized Terwilliger algebra of the hypercube 18 Tomasz Przezdziecki (U. Edinburgh)
A boundary Schur-Weyl duality functor linking quiver Hecke algebras and quantum symmetric pairs 25 Trevor Karn (U. Minnesota)
Equivariant Kazhdan-Lusztig theory of paving matroids
May
2 Hadewijch De Clercq (U. Ghent)
Defining relations for quantum symmetric pairs 9 David Keating
A vertex model for LLT polynomials

Combinatorics Seminar
U. Wisconsin-Madison Mathematics
Monday at 2:25pm
901 Van Vleck
Spring 2020 Schedule

January
27 Paul Terwilliger
The alternating central extension of the quantum affine sl2 algebra
February
3 Ian Seong
Edge-disjoint tree representation of three tree degree sequences 10 No meeting
17 Christian Gaetz (MIT)
Separable elements and splittings of Weyl groups 24 Botong Wang
Algebraic geometric perspectives of posets
March
2 Jeb Willenbring (UW Milwaukee)
Expected value of the one-dimensional Earth Mover's Distance 9 Nicholas Ovenhouse (U. Minnesota)
Poisson brackets for Grassmann pentagram map 16 Spring Recess
23 (Cancelled Covid-19) Bohdan Kivva (U. Chicago)
Proof of Babai's conjecture on the motion of distance-regular graphs 30 (Cancelled Covid-19) Emily Gunawan (U. Connecticut)
TBA
April
6 (Cancelled Covid-19) Vadim Gorin
TBA 13 (Cancelled Covid-19) Rebecca Patrias (Quebec Canada)
TBA 20 (Cancelled Covid-19) Mike Zabrocki (York U. Canada)
Symmetric group representations and the multiset partition algebra 27 (Cancelled Covid-19) Jose Rodriguez
TBA

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2019 Schedule

     
January
28 Anna Pun (Drexel U.)
Catalan Functions and k-Schur functions
February
4 Vladimir Sotirov
A Generalized Deodhar Setting for Kazhdan-Lusztig Polynomials with Applications to 4231-avoiding Permutations 11 Zachary Hamaker (U. Michigan)
Weak order for monotone triangles 15 (Friday AG seminar 2:25 B235VV) Pavlo Pylyavksyy (U. Minnesota)
Zamolodchikov periodicity and integrability 25 Alexander Heaton (U. Wisconsin-Milwaukee)
Branching from the general linear group to the symmetric group and the principal embedding
March
4 Dadong Peng
Continued fractions and walks on Farey polygons 11 Michael Tait (Carnegie Mellon)
Eight theorems in extremal spectral graph theory 18 Spring Recess
25 Ed Hanson
Krawtchouk matrices: new interpretations
April
1 Jia Huang (U. Nebraska Kearney)
Variations of the Catalan number from non-associative binary operations 8 Hao Huang (Emory U.)
A spectral proof of Kleitman's diametric theorem 15 Wesley Hough (UW Whitewater)
Discrete Morse theory and poset homomorphism complexes 22 Paul Terwilliger
The quantum affine sl2 algebra and its alternating PBW basis 29 Rinat Kedem (U. Illinois Champaign/Urbana)
Deformed Grothendieck rings from quantum cluster algebras

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2018 Schedule

     
September
10 Paul Terwilliger
Catalan words and q-shuffle algebras 17 Philippe di Francesco (U. Illinois)
Macdonald operators, from Cluster Algebra to Elliptic Hall Algebra 24 William Hardt
Support equalities among ribbon Schur functions
October
1 Edward Hanson
How to recognize a Leonard pair 8 Weiqiang Wang (U. Virginia)
A serre presentation for i-quantum groups and q-identities 15 Fabrizio Zanello (Michigan Tech.)
Unimodality of distinct-part partitions, and some related matters 22 Jonas Hartwig (Iowa State U.)
Whittaker modules for vertex operator algebras 29 Sebastian M. Cioaba (U. Delaware)
The smallest eigenvalues of Hamming, Johnson and other graphs
November
5 Paul Terwilliger
An infinite-dimensional BOXq module obtained from the q-shuffle algebra for affine sl2 12 Shamgar Gurevich
A look at representations of SL2(q) through the lens of size 19 No meeting
26 Benjamin Branman
EL-Shellings of the Order Complex of the Alternating Sign Matrix Poset
December
3 Aaron Lauve (Loyola U.)
Rational series over a free group 10 Dadong Peng
Matrices of continued fractions and Ptolemy-Plucker relations

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2018 Schedule

     
January
29 Anna Romanov (U. Utah)
A Kazhdan-Lusztig algorithm for Whittaker modules
February
5 Gene B. Kim (U. Southern California)
Distribution of descents in matchings and derangements 12 Chris Rodger (Auburn U.)
Amalgamations and Hamilton decompositions 19 Jessica Striker (N. Dakota State U.)
Poset and permutation perspectives on alternating sign matrices and certain plane partitions 26 Edward Hanson
New characterizations of Leonard pairs
March
5 Robert Laudone
Secant ideals for Plucker embedded Grassmannians 12 Morgan Rodgers (Cal State Fresno)
Cameron-Liebler sets 19 Bill Martin (WPI)
Scaffolds 26 Spring Recess
April
2 Naser Sardari
The spectra of Cayley graphs of SL2(Z/PZ) 9 Ryan Julian
Singleton Optimal Codes in the Ulam Metric 16 Benjamin Branman
A binary operation on the set of alternating sign matrices 23 Paul Terwilliger
The Lusztig automorphism of the q-Onsager algebra 30 Thomas Hameister
Chow rings of vector space matroids

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2017 Schedule

     
September
11 Paul Terwilliger
Totally bipartite tridiagonal pairs 18 Richard Brualdi
The permutation and alternating sign matrix cones 25 Arjana Zitnik (U. Ljubljana Slovenia)
Vertex-transitive graphs and their arc-types
October
2 Joshua Ducey (James Madison U.)
The critical group of a graph 9 Krystal Guo (U. Waterloo)
Quantum walks, state transfer and perturbations of graphs 16 Alexandra Kjuchukova
A combinatorial approach to the bridge number 23 Supalak Sumalroj (Silpakorn U.)
A characterization of Q-polynomial distance-regular graphs using the intersection numbers 30 Siwaporn Mamart (Silpakorn U.)
A group commutator involving the last distance matrix and dual distance matrix of a Q-polynomial distance-regular graph
November
6 Sarah Bockting-Conrad (DePaul U. Chicago)
Some linear transformations associated with a tridiagonal pair of q-Racah type 13 Stefko Miklavic (U. Primorska)
Bipartite distance-regular graphs with exactly two irreducible T-modules with endpoint 2, both thin. 20 No meeting
27 (1:20 pm, 901 VV) Yang Yang
Some problems related to the equitable presentation for the quantum algebra UqSl2
December
4 Geoffroy Bergeron (U. Montreal)
Towards bivariate q-Krawtchouk polynomials of Griffiths type 11 Mathew Lee (UC Riverside)
Global Weyl Modules and maximal parabolics for twisted affine Lie algebras

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2017 Schedule

     
January
23 Paul Terwilliger
An action of the group PSL2(Z) on a completion of Uq(sl2) 30 Eric Ramos
Stable behaviors in the unordered configuration space of a tree
February
6 Richard Brualdi
Alternating Sign Hypermatrices and a generalization of Latin Squares 13 Luc Vinet (U. Montreal)
The Bannai-Ito algebra in many guises 20 Supalak Sumalroj (Silpakorn U.)
The nonexistence of a distance-regular graph with intersection array {22,16,5;1,2,20} 27 Siwaporn Mamart (Silpakorn U.)
Merging in bipartite distance-regular graphs
March
6 Jiaoyang Huang (Harvard)
Spectra of sparse random graphs 13 Louis Deaett (Quinnipiac U.)
Matroids and the minimum rank of matrix patterns 20 Spring Recess
27 Yuta Watanabe (Tohoko U. Japan)
An algebra based on projective geometry with respect to a fixed flag
April
3 Zhaochen Wang
Tridiagonal pairs of Krawtchouk type 10 Yang Yang
Finite-dimensional irreducible BOXq-modules and their Drinfel'd polynomials 17 Darij Grinberg (U. Minnesota)
Critical groups for Hopf algebra modules 24 John Wiltshire-Gordon
Specht polytopes and matroidification
May
1 Jae-ho Lee
The generalized Terwilliger algebra of a Hamming graph

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2016 Schedule

     
September
12 Paul Terwilliger
Leonard triples of q-Racah type 19 Masato Tomiyama
The Terwilliger algebra for the incidence graph of a Hamming graph 26 Jerzy Kocik (Southern Illinois U.)
Krawtchouk matrices and SL(2)
October
3 Jing Hao
Quasi-quadratic residue codes and their weight distributions 10 Jay Yang
Random toric surfaces and a threshold for smoothness 17 Baha Balantekin (UW Physics)
From all the gold and silver in the universe to the algebraic Bethe Ansatz 24 Richard Brualdi
My second favorite Hall theorem with applications 31 Bo Lin (Berkeley)
Computing linear systems of metric graphs
November
7 Jordan Ellenberg
Variations on the cap set problem 14 Yang Yang
Some q-exponential formulas on the finite-dimensional modules of the algebra Box_q 21 Zhaochen Wang
The switching element for a Leonard pair 28 Jae-ho Lee
Dual polar graphs, a nil-DAHA of rank one, and non-symmetric dual q-Krawtchouk polynomials
December
5 No meeting
12 No meeting

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2016 Schedule

     
January
25 William Cocke
On the number of elements in a group that are not kth powers
February
1 Shamgar Gurevich
Hierarchy in Representations of SL(2,q) 8 Paul Terwilliger
Tridiagonal pairs and L-operators for Uq(sl2) 15 Wen Liu (Hebei Normal U. China)
The incidence algebra of the classical polar space poset 22 Stefan Catoiu (DePaul U. Chicago)
Pythagorean counting in rank one restricted enveloping algebras 29 Steven Sam
Constructing algebras using invariant theory
March
7 Zhaochen Wang
Introduction to tridiagonal pairs 14 Sarah Bockting-Conrad (DePaul U. Chicago)
Some q-exponential formulas involving the double lowering operator psi for a tridiagonal pair 21 Spring Recess
28 Sarah Post (U. Hawaii at Manoa)
Quadratic algebras and orthogonal polynomials
April
4 Richard Brualdi
Combinatorial Matrices 11 Daniel Erman
Laurent polynomials and Eulerian numbers 18 Jae-ho Lee (Tohoku U. Japan)
A combinatorial interpretation of the nonsymmetric Askey-Wilson polynomials 25 Masato Tomiyama
The Terwillger algebra of a bipartite graph and its bipartite half
May
2 No meeting

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2015 Schedule

     
September
7 Labor day recess
14 (in B219VV) Darren Funk-Neubauer (Colorado State U. at Pueblo)
Bidiagonal pairs and bidiagonal triples 21 (in 120 Ingraham) Eric Ramos
Generalized representation stability and FI_d-modules 28 (in 120 Ingraham) Yang Yang
Upper triangular matrices and Billiard Arrays
October
5 (in 120 Ingraham) Steven Sam
Algebraic aspects of stability of Kronecker coefficients 12 (in 120 Ingraham) Richard Brualdi
Loopy, Hankel and combinatorially skew-Hankel tournaments 19 (in 120 Ingraham) Georgia Benkart
Walking on Representation Graphs 26 (in 901 VV) Hiroyuki Yamane (U. Toyama, Japan)
Centers of generalized quantum algebras
November
2 (in 901 VV) Wen Liu (Hebei Normal U. China)
The attenuated space poset Aq(N,M) 9 (in 901 VV) Alberto Elduque (U. Zaragoza, Spain)
Octonions 16 (in 901 VV) Yuta Watanabe (Tohoku U. Japan)
An algebra based on projective geometry with one fixed subspace 23 (in 901 VV) Zhaochen Wang
The Yang-Baxter equation 30 (in 901 VV) Rafael Cantuba (De La Salle U. Manila)
Lie algebra relations in the universal Askey-Wilson algebra
December
7 (in 901 VV) Yang Yang
Generalized adjoint actions 14 (in 901 VV) Paul Terwilliger
The equitable presentation for the quantum algebra Uq(sl2)

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2015 Schedule

     
January
26 Eric Ramos
Polynomial stability for representations of combinatorial categories
February
2 Aiping Deng (Donghua U. Shanghai)
Primary modules for the tetrahedron algebra 9 Paul Terwilliger
Topological aspects of the Z3-symetric Askey-Wilson relations 16 Richard Brualdi
All things Bruhat: matrix Bruhat decomposition, Bruhat order on permutation matrices, (0,1)- and integral matrices 23 Jae-ho Lee (Tohoku U. Japan)
Nonsymmetric Askey-Wilson polynomials and Q-polynomial distance-regular graphs
March
2 Takuya Ikuta (Kobe Gakuin U. Japan)
Complex Hadamard matrices and association schemes 9 Michael Schroeder (Marshall U. WV)
Completing latin squares: Haggkvist's conjecture and disjoint subsquares 16 Alison Gordon Lynch
A graph theoretic introduction to cluster algebras 23 Thao Vu (U. Tours, France)
Higher order relations for the q-Onsager algebra
April
6 Gabriel Pretel
Benedetti and Sagan's use of involutions in the study of antipodes for Hopf algebras 13 Zhaochen Wang
An action of PSL2(Z) on the universal Askey-Wilson algebra 20 Alison Gordon Lynch
Algebraic characterizations of Cauchy pairs and Uq(sl2)-modules (PhD defense) 27 (1:20 901VV) Gabriel Pretel
Tridiagonal pairs of Krawtchouk type and their compatible elements (PhD defense)
May
4 Mark MacLean (Seattle U.)
Algebraic and combinatorial relationships in bipartite distance-regular graphs

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2014 Schedule

     
September
8 Wei-Hsuan Yu (Michigan State)
New bounds for spherical two-distance sets and equiangular line sets 15 Frank Hall (Georgia State)
G-matrices, J-orthogonal matrices, and their sign patterns 22 Apoorva Khare (Stanford)
Faces and standard parabolic subsets of highest weight modules 29 (1:20 901VV) Adam Gal (Tel-Aviv U.)
Positive self-adjoint Hopf algebras 29 (2:25 901VV) Elena Gal (Tel-Aviv U.)
Symmetric self-adjoint Hopf categories and a categorical Heisenberg double
October
6 Richard Askey
Isoperimetric inequalities for rectangular prisms, or a second look at inequalities of Newton and Maclaurin 13 Aiping Deng (Donghua U. Shanghai)
Some even dimensional modules for the tetrahedron algebra 20 Richard Brualdi
Involutions by descents/ascents and symmetric integral matrices 27 Alison Gordon Lynch
Finite-dimensional irreducible modules for an even subalgebra of Uq(sl2)
November
3 Patricia Hersh (N. Carolina State)
Representation stabiltiy and Sn-module structure in the partition lattice 10 Georgia Benkart
A pedestrian approach to representation graphs 17 Paul Terwilliger
A classification of the lowering-raising triples 24 Gabriel Pretel
Humpert and Martin's antipode formula for the incidence Hopf algebra of graphs
December
1 Andrew Loveridge
Kac Moody Algebras I 8 James Hanson
Kac Moody Algebras II

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2014 Schedule

     
January
27 Jae-ho Lee
Bilinear forms, double affine Hecke algebras, and Q-polynomial distance-regular graphs
February
3 Ameera Chowdhury (Carnegie Mellon)
A Proof of the Manickam-Miklos-Singhi Conjecture for Vector Spaces 10 Max Glick (U. Minnesota)
Two singularity phenomena 17 Richard Brualdi
Tournaments from multigraphs 24 Eliseu Fritscher (UFRGS, Brazil)
The trace index of a (0,1)-matrix
March
3 Gabriel Pretel
Distance-regular graphs of q-Racah type and the universal Askey-Wilson algebra 10 Sarah Bockting-Conrad
Tridiagonal pairs and the quantum group Uq(sl2) 17 Spring Recess
24 Paul Terwilliger
Lowering-raising triples and the quantum group Uq(sl2) 31 Aiping Deng (Donghua U. Shanghai)
Characteristic polynomials of digraphs having a semifree action
April
7 Alison Gordon Lynch
Perfect state transfer on distance-regular graphs 14 Zhongshan (Jason) Li (Georgia State University)
Minimum ranks of sign pattern matrices via sign vectors and duality 21 Shamgar Gurevich
Weil representations and explicit Mordell--Weil lattices 28 Sarah Bockting-Conrad
Tridiagonal pairs, double lowering operators, and Uq(sl2)
May
5 Pascal Baseilhac (U. Tours, France)
The reflection equation, the q-Onsager algebra, and the algebra Aq.

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2013 Schedule

     
September
9 Paul Terwilliger
Billiard Arrays and the equitable presentation of Uq(sl2) 16 Alison Gordon Lynch
Large symmetric association schemes and the P-polynomial property 23 Robin Pemantle (U. Penn)
Double-dimer configurations and the hexahedron recurrence 30 Bogdan Ion (U. Pittsburgh)
BGG reciprocity for current algebras
October
7 Cathryn Holm
Special functions associated with root systems 14 Dragan Stevanovic (U. Primorska, U. Nis)
Spectral radius of some infinite graphs 21 Gabriel Pretel
Pascal matrices 28 Bill Martin (WPI)
Spherical designs, polynomial ideals, and association schemes
November
4 Hwa-Kyung Kim (Sangmyung U.)
Completions to an alternating sign matrix 11 Richard Brualdi
Permutations, X-rays, Tournaments, Partial Latin Squares, Transversals, and Skolem sequences 18 Matthias Lenz (Oxford U.)
On splines and counting lattice points in polytopes 25 Eliseu Fritscher (UFRGS, Brazil)
Finding eigenvalues of graphs with automorphism, part I
December
2 Eliseu Fritscher
Finding eigenvalues of graphs with automorphism, part II 9 Stefko Miklavic (U. Primorska)
Q-polynomial distance-regular graphs with girth 6

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2013 Schedule

     
January
28 Paul Terwilliger
The double lowering maps for a tridiagonal pair
February
4 Edward Hanson
Characterizations of Leonard pairs 11 Alison Gordon Lynch
The interplay of ranks of submatrices 18 Gabriel Pretel
The Temperley-Lieb algebra and sl2 25 Xiang Han (U.W. Whitewater)
Some methods related to the invariant theory of groups
March
4 No seminar
11 Cathryn Holm
A new approach to the bipartite fundamental bound 18 Hwa Kim
Generalized competition index of a primitive digraph 25 Spring recess
April
1 (1:20 901 VV) Peter Tingley (Loyola U.)
Affine Mirkovic-Vilonen polytopes 1 (2:25 901 VV) Emily Peters (Northwestern)
Planar algebras and evaluation algorithms 8 Jae-ho Lee
Nonsymmetric Askey-Wilson polynomials as vector-valued polynomials 15 Richard Brualdi
A Berlekamp permutation-switching problem 22 (1:20 901 VV) Jason Gaddis (U.W. Milwaukee)
Analogs of the harmonic oscillator problem 22 (2:25 901 VV) Lauren Williams (U.W. Milwaukee)
Invariant polynomial functions on tensors under the action of a product of orthogonal groups
May
6 Sarah Bockting-Conrad
Tridiagonal pairs of height one

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2012 Schedule

     
September
10 Gabriel Pretel
Compatible elements for a tridiagonal pair 17 Sarah Bockting-Conrad
Connections between quantum sl2 and tridiagonal systems 24 Jae-ho Lee
Q-polynomial distance-regular graphs and the DAHA of rank one
October
1 Paul Terwilliger
Finite dimensional irreducible Uq(sl2)-modules from the equitable point of view 8 Jang Soo Kim (U. Minnesota)
Moments of Askey-Wilson polynomials 15 Cathryn Holm
The girth of a thin distance-regular graph 22 Richard Brualdi
Alternating sign matrices and their patterns 29 Alison Gordon
Erdos-Ko-Rado theorems for Q-polynomial distance regular graphs
November
5 Vincent Genest (U. Montreal)
On the Clebsch-Gordan and Racah problems of sl_{-1}(2) and (-1)-orthogonal polynomials 12 Jonah Blasiak (U. Michigan)
Kronecker coefficients for one hook shape 19 Georgia Benkart
Combinatorics on the Weyl Side 26 Shamgar Gurevich
Bounds on characters of SL(2,q) via theta correspondence, with applications to the Ore conjecture
December
3 Zajj Daugherty (Dartmouth)
The quasi-partition algebra 10 Nathan Manning (U. Ottawa)
Global Weyl modules for equivariant map algebras

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2012 Schedule

     
January
23 Seth Meyer
Patterns of alternating sign matrices 30 Vidya Venkateswaran (CalTech)
Vanishing integrals for Hall-Littlewood polynomials
February
6 Ed Hanson
Fiedler's characterization of tridiagonal matrices 13 Sarah Bockting
Nomura's refinement of the split decomposition for a tridiagonal pair 20 Paul Terwilliger
The universal Askey-Wilson algebra 27 Tullia Dymarz
Rigidity and enveloping discrete groups by locally compact groups
March
5 Jonathan Lima
Symmetric function inequalities and Y-positivity 12 Thomas Roby (Visiting MIT)
Equivalence relations of permutations generated by constrained transpositions 19 Shuchi Chawla (UW CS dept)
Pricing via prophet inequalities 26 Gabriel Pretel
Finite-dimensional modules for the sl2 loop algebra
April
2 Spring Recess
9 Richard Brualdi
From classical majorization to poset majorization 16 Alison Gordon
An introduction to algebraic codes 23 Georgia Benkart
The McKay correspondence and walks on diagrams 30 Boyd Worawannotai
Dual polar graphs, the quantum sl2 algebra, and Leonard systems of dual q-Krawtchouk type
May
7 Jae-ho Lee
The Askey-Wilson algebra AW(3) and the double affine Hecke algebra of rank one 14 Stefko Miklavic (U. Primorska, Slovenia)
On distance-regular Cayley graphs for abelian groups

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2011 Schedule

     
September
12 Richard Brualdi
Matrix classes: old and new 19 Bostjan Frelih (U. Primorska, Slovenia)
Classification of cubic symmetric pentacirculants 26 Jernej Tonjek (U. Ljubljana, Slovenia)
A new inequality for distance-regular graphs
October
3 Melanie Matchett Wood
Counting points in configuration spaces 10 Amos Ron (UW CS dept)
Zonotopal algebra over finite graphs 17 Shamgar Gurevich
Fast matched filter and group representations: what, why, and how? 24 Gabriel Pretel
The A-like matrices for a hypercube 31 Boyd Worawannotai
Bipartite Q-polynomial distance-regular graphs and uniform posets
November
7 Eric Bach (UW CS dept)
An introduction to Widgetology 14 Philip Matchett Wood
Subset sums avoiding a single value 21 Seth Meyer
Isomorphisms of bipartite circulant graphs 28 Jae-ho Lee
Classification of the irreducible finite-dimensional representations for the double affine Hecke algebra of rank 1
December
5 Dima Arinkin (UNC-Chapel Hill)
Autoduality of Jacobians for singular curves 12 Alison Gordon
Cauchy pairs and Cauchy transition matrices

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2011 Schedule

     
January
24 Hajime Tanaka
A note on super Catalan numbers 31 Ana-Maria Castravet
Hypertrees and moduli spaces of stable rational curves
February
7 Dongho Moon
Permutation patterns and representation theory 14 George Brown
Leonard triples associated with hypercubes and their antipodal quotients 21 Seth Meyer
Bipartite circulant graphs and zero forcing 28 Gabriel Pretel
Baseilhac's hierarchy of mutually commuting elements in the tridiagonal algebra
March
7 Rie Tanaka
On a class of wreath products of hypergroups 14 Spring Recess
21 Georgia Benkart
Planar rook algebras and tensor representations of gl(1|1) 28 Michael Schroeder
Symmetric Hamilton cycle decompositions; some special cases
April
4 Alison Gordon
Cauchy pairs and transition matrices 11 "Turbo" Meng-Che Ho
Determinants of some tridiagonal matrices 15 (2:25 901 VV) Kailash Misra (North Carolina State U.)
Quantum groups and crystal bases 18 Jae-ho Lee
T-modules for Q-polynomial distance-regular graphs with a Delsarte clique 25 Sarah Bockting
Uq(sl2)-modules arising from tridiagonal systems
May
2 Shamgar Gurevich
Detecting the symmetry group of a molecule using cryo-electron microscopy

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2010 Schedule

     
August
30 Sarah Bockting
An operator associated with tridiagonal pairs
September
6 Labor day holiday
13 Paul Terwilliger
The classification of sharp tridiagonal pairs 20 Richard Brualdi
Matrices and Indeterminates 27 Sho Suda (Tohoku U. Japan)
Complex spherical designs and codes
October
4 Oleg Musin (U. Texas at Brownsville)
Positive definite functions in distance geometry 11 Boyd Worawannotai
Dual polar graphs and the quantum algebra Uq(sl2) 18 Michael Schroeder
phi-Hamilton cycle decompositions of the complete multipartite graph REDUX 25 Hajime Tanaka
Subsets with minimal width and dual width in Q-polynomial distance-regular graphs
November
1 Rie Tanaka
On the Terwilliger algebra of the Hamming graph with respect to a subset 8 Rachel Quinlan (U. Galway, Ireland)
Spaces of matrices without non-zero eigenvalues in their field of definition 15 Shifra Reif (Weizmann Institute)
Denominator identities for Lie superalgebras 22 Hiroshi Nozaki (Tohoku U. Japan)
Few distance sets and the Larman-Rogers-Seidel theorem 29 Hau-wen Huang
The classification of Leonard triples that have QRacah type
December
6 Edward Hanson
Leaves, tails, and Leonard pairs 13 Ali Godjali
Thin Hessenberg pairs and double Vandermonde matrices

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2010 Schedule

     
January
25 Paul Terwilliger
Double affine Hecke algebras of rank 1 and the Z3-symmetric Askey-Wilson relations
February
1 Rahbar Virk
An introduction to the combinatorics of category O 8 Hau-wen Huang (National Chiao Tung University, Taiwan)
The lit-only "sigma" game on a finite simple graph 15 Stefko Miklavic (U. Primorska, Slovenia)
On vertex-stabilizers of bipartite dual polar graphs 22 Richard Brualdi
(0,1)-Matrices and nonnegative eigenvalues
March
1 Seth Meyer
Computation of a generalization of the term rank of a semi-regular (0,1) matrix using a version of Hall's Theorem 8 Raimundas Vidunas (Kobe University, Japan)
Transformations between Heun and hypergeometric equations 15 Edward Hanson
Orthogonal polynomials and tridiagonal matrices 22 Gabriel Pretel
Four algebras related to tridiagonal pairs 29 Spring recess
April
5 Vladimir Tonchev (Michigan Tech)
Quantum codes from finite geometry and combinatorial designs 12 Rie Tanaka (Tohoku U. Japan)
On the association schemes with almost commutative Terwilliger algebras 19 Emeric Deutsch (Polytechnic Institute of New York U.)
Adjacent q-cycles in permutations 26 Michael Schroeder
phi-invariant Hamilton cycle decompositions
May
3 Gernot Michael Engel
Newton's inequalities on a lattice

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2009 Schedule

     
August
31 Edward Hanson
A characterization of Leonard pairs in terms of tails
September
7 Labor day
14 Aleksandar Jurisic (U. Ljubljana Slovenia)
The search for new distance-regular graphs 21 Xiaoguang Ma (MIT)
Quantum symmetric pairs and double affine Hecke algebras 28 Martha Yip
A Littlewood-Richardson rule for Macdonald polynomials
October
5 Don Kreher (Mich. Tech)
The degree sequence problem for partial Steiner triple systems 12 David Clark (Mich. Tech)
Designs, geometries, and Hamada's conjecture 19 Seth Meyer
Zero forcing sets 26 Ali Godjali
Thin Hessenberg pairs
November
2 Diana Cerzo
Thin irreducible T-modules for Q-polynomial distance-regular graphs 9 Hiroshi Suzuki (ICU Japan)
Tridiagonal spaces and Leonard pairs 16 Richard Brualdi
Completion of partial matrices to singular/nonsingular matrices 23 Michael Schroeder
Symmetric Hamilton cycle decompositions of graphs 30 Bridget Tenner (DePaul U.)
Homotopy type of the boolean complex of a Coxeter system
December
7 Sergei Sergeev (U. Birmingham UK)
Powers of matrices and periodicity questions in max algebra 14 Ales Drapal
Latin bitrades, equilateral triangles and abelian groups

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2009 Schedule

     
January
26 Paul Terwilliger
The Drinfel'd polynomial of a tridiagonal pair
February
2 Boyd Worawannotai
A Tutte polynomial for signed graphs 9 Diana Cerzo
Imprimitive Q-polynomial schemes 16 Ali Godjali
Properties of graded polynomial sequences and their duals 23 Adam Berliner
The Pesky Permanent Problem
March
2 Mihai Ciucu (U. Indiana)
Random tilings with gaps and electrostatics 9 Zajj Daugherty
Building my favorite centralizer algebras 16 Spring break
23 Richard Brualdi
Potentially nilpotent full sign patterns are spectrally arbitrary - a theorem of R. Pereira 30 Gabriel Pretel
q-geometric tridiagonal pairs and the quantum affine sl2 algebra
April
6 Louis Deaett
The sparse null space basis problem 13 Seth Meyer
Signed edge domination numbers in bipartite graphs 20 (1:20 901 VV) Hajime Tanake (Tohoku U. Sendai)
A bilinear form relating two Leonard systems 20 (2:25 901 VV) Rie Tanake (Tohoku U. Sendai)
Imprimitive Q-polynomial association schemes 27 Mike Schroeder
Latin squares composed of intercalates
May
4 Anna Saputera
Line graphs, root systems, and elliptic geometry 11 (2:00 pm, 901 VV) Boyd Worawannotai
Toward the cyclicly symmetric Askey-Wilson relations for dual polar graphs

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2008 Schedule

     
September
8 Paul Terwilliger
The classification of tridiagonal pairs of q-Racah type 15 Michael Gekhtman (Notre Dame)
Planar networks, Grassmannians and Poisson structures 22 George Brown
The Smith normal norm and acyclic matrices 29 Aleksandar Jurisic (U. Ljubljana Slovenia)
Distance-regular graphs with light tails
October
6 Michael Lang (Bradley U.)
Entrywise products of pseudo primitive idempotents 13 Plamen Iliev (Georgia Tech.)
Bispectrality of multivariable orthogonal polynomials 20 Bill Martin (WPI)
Lattices, mutually unbiased bases, hemisystems, and Q-polynomial association schemes. 27 Stefko Miklavic (U. Primorska, Slovenia)
The subconstituent algebra of a bipartite distance-regular graph
November
3 Richard Brualdi
Landau's and Rado's Theorems and partial tournaments 10 Louis Deaett
The minimum positive-semidefinite rank of a triangle-free graph 17 Andrei Calderaru
A spectral sequence from the ribbon graph bicomplex 24 Vadim Olshevsky (U. Connecticut)
Quasiseparable matrices and polynomials
December
1 Adam Berliner
TBA 8 Sergei Sergeev (U. Birmingham UK)
Two sided linear systems over max algebra

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2007 Schedule

     
January
22 Richard Brualdi
Matrix diagonals: something old and something new 24 (1:30, 901VV) Bridget Tenner
Reduced decompositions and permutation patterns 29 Dong-il Lee (Seoul Natl. U.)
Linear algebraic approach to Groebner-Shirshov basis theory
February
5 Amos Ron (U.W. Comp. Sci. Dept.)
Polynomial ideals and polynomial spaces over hyperplane arrangements and zonotopes 12 Stefko Miklavic (U. Ljubljana Slovenia)
Consistent cycles 19 Christoph Schwer
Galleries and q-analogs of symmetric functions 26 Paul Terwilliger
Evaluation modules for the three-point sl2 loop algebra
March
5 Jon Godshall
The q-tetrahedron algebra and the split decomposition of a Leonard Pair 12 (3:30 B131VV) Stefko Miklavic
Leonard triples and the hypercubes 19 Bill Martin (WPI)
Large bounds for binary codes from the subconstituent algebra 26 Kathleen Kiernan
Latin squares with forbidden entries
April
2 Spring break
9 Louis Deaett
Structural properties of triangle-free graphs 16 Lauren Williams (Harvard)
From total positivity on the Grassmanian to the asymmetric exclusion process 23 Mike Schroeder
The m-colored composition poset 30 Melvin Vidar
A family of tridiagonal pairs
May
7 Joohyung Kim
A duality between pairs of split decompositions for a Q-polynomial distance-regular graph 9 (2:25, B333 VV) Helene Barcelo (Arizona State U.)
The discrete fundamental group of the order complex of Bn

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2006 Schedule

     
September
11 Richard Brualdi
Matrix diagonals 18 Bill Martin (WPI)
An update on (t,m,s)-nets 18 (3:30pm, B341 VV) Alberto Grunbaum (Berkeley)
An ab-initio introduction to the bispectral problem 25 Bill Martin
Design systems: combinatorial characterizations of Delsarte T-designs
October
2 Arjana Zitnik (U. Ljubljana Slovenia)
Triangle-free distance-regular graphs with an eigenvalue multiplicity equal to the valency and diameter three 2 (3:30pm, B341 VV) Aleksandar Jurisic (U. Ljubljana Slovenia)
Characterization of the Patterson graph by its intersection array 9 Paul Hermann Zieschang (U. Brownsville TX)
Recent results and general questions in abstract scheme theory 16 James Parkinson
Iwahori cosets and alcove walks 23 Terry Gannon (U. Alberta CA)
What the trefoil knot can teach modular forms 30 Paul Terwilliger
Distance-regular graphs and the q-tetrahedron algebra
November
6 Claudia Malvenuto, University of Rome, La Sapienza
Pairwise colliding permutations and the capacity of infinite graphs 13 George Brown
Packing densities of layered permutations 20 Joohyung Kim
Characterization of some strongly regular graphs with parameters (64,28, 12, 12) 27 Ales Drapal
Latin trades and surfaces
December
4 (B305 VV) Ashwin Ganesan (U.W. ECE dept.)
Flows in information networks 11 Adam Berliner
Converting the permanent to the determinant

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2006 Schedule

     
January
23 Paul Terwilliger
The q-tetrahedron algebra 30 Richard Brualdi
Even posets and a parity result of Yaokun Wu
February
6 Susan Hollingsworth
The log-concavity of a famous sequence counting permutations 13 Jin-Yi Cai (UW Comp. Sci. Dept.)
Some results on matchcircuit computations and holographic algorithms 20 Christine Heitsch
Kreweras Complementation and Orbits in Catalan Lattices 27 Arun Ram
The Schur Hopf algebra
March
6 Lev Borisov
Introduction to the Leech lattice 13 Spring break
27 Martin Schlichenmaier (U. Luxembourg)
Higher genus affine Lie algebras of Krichever-Novikov type
April
3 Benjamin Otto
The Lie algebra G2 10 Jon Godshall
The universal central extension of the tetrahedron algebra 17 Han Hyuk Cho
Unicyclic graphs and competition numbers 24 Louis Deaett
Complexity and the structure of low-rank matrices
May
1 Patricia Hersh (U. Indiana)
The q=-1 phenomenon via homology concentration 5 Don Cartwright (U. Sydney, Rutgers) (2:25pm, B333 Van Vleck)
Groups acting simply transitively on the vertices of a building

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2005 Schedule

     
September
12 Paul Terwilliger
Distance-regular graphs and the quantum affine sl2 algebra 19 David Callan (UW Dept. of Statistics)
Generalizing the Catalan numbers 26 Nigel Boston
Risk and return considerations in The Weakest Link
October
3 Kathrin Bringmann
On mock theta functions and a conjecture of Dragonette and Andrews 10 Richard Brualdi
Latin squares, matroids, partitions, (0,1)-matrices, Young tableaux, graphs, matchings,... 17 Mikhail Klin (Ben Gurion U. Israel)
Links between Latin squares, nets, graphs and groups: work inspired by a paper of A. Barlotti and K. Strambach 24 Etsuko Bannai (Kyushu U. Japan)
On Euclidean designs 31 Sharon Garthwaite
Convolution congruences for the partition congruences
November
7 John Goldwasser (West Virginia U.)
Maximum size antichains and the COLEX order 14 Brian Hartwig
The tetrahedron algebra 21 Jackie Anderson
The largest (s,t)-core partition 28 Dina Christodoulopoul
An introduction to affine Weyl groups
December
5 H.K. Kim (Seoul Natl. U. Korea)
Competition indices of primitive digraphs 12 Louis Deaett
More on the Bruhat order for (0,1)-matrices

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2005 Schedule

     
January
24 Paul Terwilliger
Bidiagonal triples and the quantum algebra Uq(sl2) 31 Richard Brualdi
Some remarks on the Bruhat order for (0,1) matrices
February
7 Brian Hartwig
Onsager pairs and the Tetrahedron algebra 14 Richard Askey
q-factorial, q-gamma and q-beta functions 21 Nigel Boston
Capacity-achieving graph-based codes 28 Georgia Benkart
A combinatorial tripleheader: lambda-determinants, Schur functions, and perfect matchings
March
7 Christine Heitsch
Random de Bruijn sequences and the design of DNA codewords 14 Adam Berliner
Sidon sequences and magic graphs 21 Spring break
28 Han Cho
Competition graphs and numbers
April
4 Jim Propp
The combinatorics of Markoff numbers 11 Susan Hollingsworth
Cycle decompositions and path packings of K_nn 18 Bret Benesh
A survey of probabilistic group theory 25 Stephan Griffeth
TBA
May
2 Arlene Pascasio (U. De La Salle Philippines)
The pseudo primitive idempotents of a distance-regular graph

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2004 Schedule

     
September
13 Kyle Petersen (Brandeis)
Descent algebras and P-partitions 20 John Bowman
Symmetric functions and the cohomology of Springer fibers 27 Paul Terwilliger
The compact representation of a Leonard pair
October
4 Cathy Yan (Texas AM)
Noncrossing and nonnesting matchings 11 Richard Brualdi
Perfect Matching Preservers 18 Jaclyn Anderson
A proof of a conjecture of Stanton 25 Karl Mahlburg
A new approach to cranks and ranks
November
1 Jeremy Lovejoy (CNRS)
Extending partition theorems of Schur and Gollnitz to overpartitions 8 Pascal Vontobel
The edge zeta function of graphs and enumerating backtrackless, tailless cycles 15 Stefko Miklavic (Nova Gorica)
Some equitable partitions of Q-polynomial distance-regular graphs 22 Jose Dias da Silva (Lisbon)
Orthogonal dimension of orbital sets 29 Bob Wilson
Rook numbers and the normal ordering problem
December
6 Dina Christodoulopoul
Cluster algebras 13 Arun Ram
Paths, charge and Kostka-Foulkes polynomials

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2004 Schedule

     
January
26 Dick Askey
A determinant of Sylvester and some extensions
February
2 Stephen Griffeth
Schubert calculus, Hecke algebras, and the Yang-Baxter equation 9 Arun Ram
A new look at the path model 16 Paul Terwilliger
An extension of the quantum affine sl2 algebra 23 Open
March
1 Open
8 Adam Berliner, Rike Bostelmann, Louis Deaett
Sum choice numbers of graphs 15 Spring break
22 John Caughman (Portland State U.)
Distance-regular graphs and spin models 29 Holly Swisher
The Andrews-Stanley partition function and p(n)
April
5 Jose Dias da Silva
TBA 12 Marcelo Aguiar (Texas AM)
Loday's types of algebras and Rota's types of operators 19 Brian Hartwig
Three mutually adjacent Leonard pairs 26 Christine Heitsch
Further combinatorial results motivated by computational biology
May
3 Darren Neubauer
Raising and lowering maps and modules for the quantum affine sl2 algebra 10 John Hall
Semigroups and combinatorics: radicals, Schur functions, and sandwich matrices

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2003 Schedule

     
September
8 Jim Propp
Markoff numbers 15 Yuval Roichman (Bar Ilan)
Descent representations and the flag major index 22 Sergey Fomin (U. Michigan)
Double Bruhat cells: total positivity and cluster algebras 29 Slavik Jablan (Belgrade)
The Knot-theory program LinKnot
October
6 Jaclyn Anderson
On the existence of rook equivalent t-cores 13 Mona Musa (U. Illinois)
The double circulant conjecture for quadratic residue codes 20 No meeting
27 Lev Borisov
Complexity of binomial ideals
November
3 Richard Brualdi
Bigraphs, digraphs, SNS-matrices, tilings, and Aztec diamonds 10 Peter Orlik
Ranking patterns 17 Ada Chan (Caltech)
Jones pairs and association schemes 24 Patricia Hersh (U. Michigan)
A GL_n(q) analog of the partition lattice
December
1 Matt Ondrus
Whittaker modules, central characters and tensor products of modules for U_q(sl_2) 8 Susan Hollingsworth
k-ordered bipartite graphs

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Spring 2003 Schedule

     
January
27 Christine Heitsch
Combinatorial results motivated by computational biology

Combinatorics Seminar
Monday at 2:25pm
901 Van Vleck
Fall 2000 Schedule

     
September
11 Alexsandar Jurisic (Nova Gorica Polytechnic, Slovenia)
Distance-regular graphs with the 1-homogenous property 18 Paul Terwilliger
Leonard pairs from 24 points of view 25 Susan Hollingsworth
Partitions of a graph into paths with prescribed endvertices and lengths
October
2 Arun Ram
Standard Young tableaux for classical type root systems 9 Jeremy Lovejoy
Arithmetic properties of combinatorial functions 16 Chris Godsil (U. Waterloo, CA)
Spin Models 23 Bill Martin (Worcester Polytechnic)
Width and Dual Width of Subsets in P- and Q- polynomial schemes 30 Katsuhisa Mimachi (Kyushu U. Japan)
Monodromy representations associated with a Selberg type integral; realization of the Iwahori-Hecke algebra
November
6 Robert Donnelly (Murray State U.)
Solitary bases for representations of semisimple Lie algebras 13 Norman Wildberger
A-D-E graphs and the mutation and numbers games 20 Georgia Benkart
Tensor powers of sl(r) 27 Andrei Kelarev
On transitive Cayley graphs of groups and semigroups
December
4 Mark Maclean
Latin squares without proper subrectangles 11 John Caughman (Portland State U.)
Bipartite distance-regular graphs with the Q-polynomial property