University of Miami Combinatorics Seminar
Organizers: Bruno Benedetti and Michelle Wachs
When not specified, we meet at 5pm on Mondays, in Ungar Building, Room 402.
Click on the dates for the abstracts.
Spring 2023
January 30: Michelle Wachs (U Miami), On q-unimodality of generalized Gaussian coefficients and LLT polynomials
February 20: Hsin-Chieh Liao (U Miami), Chow rings and augmented Chow rings of uniform matroids and their q-analogs
March 13: Spring Break
April 17: Lisa Seccia (U Genoa), TBA
May 1: Igor Pak (UCLA), Colloquium TBA
Fall 2022
September 19 : Bruno Benedetti (U Miami), Random Simple Homotopy Theory
Thursday, October 6 : Kyle Celano (U Miami), RSK and S_n-action for P-tableaux of 3-free Natural Unit Interval Orders
December 5 : Yuval Roichman (Bar-Ilan U, Israel), Gallai colorings, transitivity and Schur-positivity
Spring 2022
February 14 : Richard Stanley (U Miami, MIT), A Fibonacci Analogue of Pascal's Triangle
February 21 : Bruno Benedetti (U Miami), Vertex Labeling Properties for Simplicial Complexes
February 28 : Marta Pavelka (U Miami), 2-LC triangulated manifolds are exponentially many
March 7 : Kyle Celano (U Miami), Geometric Bases of Hessenberg Varieties and the Stanley-Stembridge Conjecture
March 14 : Mark Skandera (Lehigh U), Symmetric generating functions and permanents of totally nonnegative matrices
March 21: no seminar
March 28: Hsin-Chieh Liao (U Miami), Stembridge codes, Chow rings of Boolean matroids, and their extensions
April 4: no seminar
April 11: no seminar due to Faculty Senate Awards
April 18: no seminar due to department meeting
April 25: Michelle Wachs (U Miami), On an n-ary generalization of the Lie representation
Spring 2020
February 11 (Tuesday 5PM): Richard Stanley (U Miami, MIT), Persification
February 17: Carly Klivans, (Brown U), Flow-firing processes
February 24: Matteo Varbaro (U Genova, Italy), Square-free Gr?bner degenerations
March 2: Mark Skandera (Lehigh U), Generating functions for induced characters of the hyperoctahedral group
March 9: Spring Break
March 30: Rafael González D'León (Sergio Arboleda U, Colombia), TBA
Spring 2019
January 22: Emanuele Delucchi (U Fribourg, Switzerland), Stanley-Reisner rings of symmetric simplicial complexes
February 4: Eric Katz (Ohio State), The Unipotent Torelli Theorem for Graphs
February 18: Francesco Brenti (U Roma 2, Italy), Permutations, tensor products, and Cuntz algebra automorphisms
February 25: Marta Pavelka (UM), On a paper by Delucchi and Hoessly
February 28 (Colloquium): Sergey Fomin (U Michigan)
March 25: Fabrizio Zanello (MTU), On the parity of the partition function
April 8: Rafael González D'León (Sergio Arboleda U, Colombia)
April 22: Morgan Brown (UM)
April 29: Federico Castillo (U Kansas)
Fall 2018
September 24: José Alejandro Samper (UM), Round polytopes
October 1: Bruno Benedetti (UM), Random preprocessing in computational topology
October 8: Alex Lazar (UM), On the Intersection Lattice of the Homogenized Linial Arrangement
October 15: Amzi Jeffs (U Washington), Convex Union Representability of Simplicial Complexes
October 29: Joseph Doolittle (Kansas U), Reconstructing Spheres and Polytopes
November 12: Alejandro Ginory (Rutgers), Positivity Conjectures for Jack Polynomials
December 3 (4pm in UB 506): Zvi Rosen (Florida Atlantic University), Combinatorial Neural Codes
SPRING 2018
January 22: Richard Stanley (U Miami & MIT), The Sperner property
January 29: Jai Aslam (Northeastern), Intersection patterns of sets
February 5: Bruno Benedetti (U Miami), Some contractible 2-complexes do not embed in R^4
February 19: Michelle Wachs (U Miami), On enumerators of Smirnov words by descents and by cyclic descents
March 5: Jessica Striker (North Dakota State U), Sign matrix polytopes
March 19: José Alejandro Samper (U Miami), Threshold hypergraphs revisited
March 27: Tue. 5PM (dissertation defense) Brittney Ellzey (U Miami), The chromatic quasisymmetric function of directed graphs
April 3: Tue. 5PM (colloquium) Fu Liu (UC Davis), Ehrhart Positivity
April 9: Bruno Benedetti (U Miami), Parity arguments in combinatorics and beyond
April 16: Felix Gotti (UC Berkeley), A connection between tilings and matroids on the lattice points of a regular simplex
April 23: Alex Lazar (UM), The Homogenized Linial Arrangement
April 30: Takayuki Hibi (Osaka U), TBA
FALL 2017
August 21: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
August 28: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
September 4: Labor Day
September 11: Brittney Ellzey (U Miami), CANCELLED DUE TO IRMA
September 11: James McKeown (U Miami), CANCELLED DUE TO IRMA
September 18: José Alejandro Samper (U Miami), CANCELLED DUE TO IRMA
September 25: Tiago Novello de Brito (Pontifícia Universidade Católica do Rio de Janeiro), Discrete Line Field
October 9: MSRI workshop, no seminar this week
October 16: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
October 23: Manuel Rivera (U Miami), A combinatorial model for the based loop space
October 30: Brittney Ellzey (U Miami), Chromatic quasisymmetric functions of directed graphs
November 6: Michelle Wachs (U Miami), Chromatic quasisymmetric functions and Hessenberg varieties
November 13: James McKeown (U Miami), Tilings of Space and the Dedekind-MacNeille completion of Bruhat order
November 20: Thanksgiving break, no seminar this week
December 4: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
December 11: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
December 18: José Alejandro Samper (U Miami), Hopf Algebras in Combinatorics
SPRING 2017
January 23: Richard Stanley (U Miami & MIT), Counting with congruence conditions
January 30: Bruno Benedetti (U Miami), Mogami constructions of manifolds from trees of tetrahedra
February 6: José Samper Casas (UM), On conjectural relatives of matroid polytopes
February 13: Brittney Ellzey (UM), A directed graph generalization of chromatic quasisymmetric functions
February 17, 4pm: Sebi Cioaba (U Delaware), Simplicial rook graphs: algebraic and combinatorial properties
February 20: Hai Long Dao (U Kansas), On local-global phenomena in the Betti tables of Stanley-Reisner ideals
February 27: Yuval Roichman (Bar-Ilan U, Israel), Cyclic descents of standard Young tableaux
February 28 Tue., 5PM (colloquium): Ron Adin (Bar-Ilan U, Israel), Cyclic descents, toric Schur functions and Gromov-Witten invariants
March 6: Laura Escobar (Urbana Champaign), Rhombic tilings and Bott-Samelson varieties
March 7 Tue., 5PM (colloquium): Anders Björner (KTH, Sweden), Around codimension one embeddings
March 13: Spring break
March 20: Fabrizio Zanello (Michigan Tech), Partition into distinct parts and unimodality
March 27: Tewodros Amdeberhan (Tulane), Determinants in "Wonderland"
April 3: Felix Gotti (UC Berkeley), Dyck paths and positroids from unit interval orders
April 10: Passover (no seminar this week)
April 17: Michelle Wachs (U Miami), On r-inversions and symmetric functions
April 24: Vasu Tewari (U Washington), Labeled binary trees, Schur-positivity and generalized Tamari lattices
FALL 2016
August 29: Hailun Zheng (U Washington), A characterization of simplicial manifolds with g2 ≤ 2
September 5: Labor day (no seminar this week)
September 12: Jay Yang (U Wisconsin-Madison), Random toric surfaces and a threshold for smoothness
September 19: Alessio Sammartano (Purdue), Blowup algebras of rational normal scrolls
September 24-26: AMS Sectional meeting (Maine), no seminar this week
October 3: Nancy Abdallah (Linkoeping U, Sweden), Bruhat order on twisted identities and KLV polynomials
October 6 (Colloquium): Frank H. Lutz (TU Berlin, Germany), On the Topology of Steel
-- canceled due to hurricane Matthew
October 17: Anastasia Chavez (UC Berkeley), The Dehn-Sommerville relations and the Catalan matroids
October 24: Rainer Sinn (Georgia Tech), Positive semidefinite matrix completion and free resolutions
October 31: Katharina Jochemko (TU Wien, Austria), Discrete vs. continuous valuations: similarities and differences
November 7: Alex Lazar (UM), Filtered geometric lattices
November 14: John Shareshian (Washington U.), Subrack lattices of group racks
November 21: Jim Haglund (U Penn), LLT polynomials and the chromatic symmetric function of unit interval orders
SPRING 2016
January 25: Alex Engstr?m (Aalto U, Finland), Boolean Statistics
February 1, 4pm: Richard Stanley (UM & MIT), Parking functions and their generating function. (Please note unusual time)
February 9 (!): Yuval Roichman (Bar-Ilan U, Israel), Geometric grid classes and symmetric sets of permutations
February 15: Matteo Varbaro (U Genova, Italy), Dual graphs and the Castelnuovo-Mumford regularity of subspace arrangements
February 22: ?Russ Woodroofe (Mississippi State), A Broad Class of Shellable Lattices
February 29, 4pm: ?Cynthia Vinzant (North Carolina State U), Real stable polynomials, determinants, and matroids. (Please note unusual time)
March 7: spring break
March 14, 4pm: Mark Skandera (Lehigh U), Evaluations of the power sum traces at Kazhdan-Lusztig basis elements of the Hecke algebra. (Please note unusual time)
March? 17 (!): Emanuele Delucchi (U Fribourg, Switzerland), Toric arrangements and group actions on semimatroids
March 21: Luca Moci (Jussieu-Paris 7, France), Higher dimensional colorings and flows, arithmetic Tutte polynomials, and convolution formulae
March 28: James McKeown (UM), The combinatorics of the Waldspurger decomposition
April 4: Marty Golumbic (U Haifa, Israel), New and Old Graph Dimension Parameters
April 11, 4pm: Efrat Engel Shaposhnik (MIT), Dissertation Defense: Antichains of Interval Orders and Semiorders, and Dilworth Lattices of Maximum Size Antichains
April 18: Brittney Ellzey (UM), The Chromatic Quasisymmetric Function of the Cycle
April 25: Miriam Farber (MIT), Weak Separation, Pure Domains, and Cluster Distance
FALL 2015
September 21: Michelle Wachs (UM), Weighted bond posets and graph associahedra I
September 28: Michelle Wachs (UM), Weighted bond posets and graph associahedra II
October 5: Florian Frick (Cornell), Tverberg-type theorems and zero sum problems
October 12: Ivan Martino (U Fribourg, Switzerland),? Arrangements of subspaces for finite groups and their geometrical applications
October 17-18: AMS sectional meeting (Memphis); no seminar this week
October 26: Bennet Goeckner (Kansas U),? A non-partitionable Cohen-Macaulay complex
November 2: Brittney Ellzey (UM), Power sum expansion of the chromatic quasisymmetric functions
November 10 (!): Jose Samper (U Washington),
Relaxations of the matroid axioms.
?5pm, Ungar 402 -? note the change of date!
November 16: Bruno Benedetti (UM), Optimal discrete Morse vectors are not unique.
November 23: Thanksgiving break. Enjoy!
November 30: Barbara Bolognese (Northeastern U, Boston),? Dual graphs of projective curves.
December 7: Carolina Benedetti (Fields
Institute and York U, Toronto, Canada): Chromatic symmetric functions on
simplicial complexes