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 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

Past sessions

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


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



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



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



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