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Award Abstract # 1764012
Combinatorial Connections with Algebra, Geometry, Probability and Applications

NSF Org: DMS
Division Of Mathematical Sciences
Recipient: UNIVERSITY OF WASHINGTON
Initial Amendment Date: August 1, 2018
Latest Amendment Date: August 12, 2020
Award Number: 1764012
Award Instrument: Continuing Grant
Program Manager: Stefaan De Winter
sgdewint@nsf.gov
 (703)292-2599
DMS
 Division Of Mathematical Sciences
MPS
 Directorate for Mathematical and Physical Sciences
Start Date: August 1, 2018
End Date: July 31, 2023 (Estimated)
Total Intended Award Amount: $187,269.00
Total Awarded Amount to Date: $187,269.00
Funds Obligated to Date: FY 2018 = $131,023.00
FY 2020 = $56,246.00
History of Investigator:
  • Sara Billey (Principal Investigator)
    billey@math.washington.edu
Recipient Sponsored Research Office: University of Washington
4333 BROOKLYN AVE NE
SEATTLE
WA  US  98195-1016
(206)543-4043
Sponsor Congressional District: 07
Primary Place of Performance: University of Washington
WA  US  98195-0001
Primary Place of Performance
Congressional District:
07
Unique Entity Identifier (UEI): HD1WMN6945W6
Parent UEI:
NSF Program(s): Combinatorics
Primary Program Source: 01001819DB NSF RESEARCH & RELATED ACTIVIT
01002021DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):
Program Element Code(s): 797000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.049

ABSTRACT

Combinatorics is an area of mathematics which is quintessential for applications in computer science, biology, physics, chemistry, and industry. Optimized algorithms based on combinatorics have revolutionized business decisions in our lifetime. Current research is uncovering connections to all areas of mathematics and science. This project focuses specifically on interdisciplinary applications of combinatorics in connection with problems in algebra,geometry, probability, and computer science. Combinatorial connections have been at the core of the investigator's prior work and continue to inspire innovation and collaboration.

This project describes three main themes for research. The first relates to the classical study of the coinvariant algebra and its representation theory. The problem is to study the asymptotics of the underlying decomposition into irreducible symmetric group modules. The methods of attack include tools from combinatorics, algebra and probability theory. The second studies a newly proposed family of symmetric functions related to the matroid of 0-1 vectors in n-dimensional space. Conjectures and theorems in this direction use tools from algebraic geometry. This research has connections to physics and economics. The third topic, which is a mixture of combinatorics, theoretical computer science and discrete geometry, pertains to placements of circles in the plane with a wrapping condition. This area of research was inspired by the general discrete geometry problem of finding an appropriate polygonization of a region in the plane which appears in graphics and optimization.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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ASINOWSKI, A. "POP-STACK SORTING AND ITS IMAGE:PERMUTATIONS WITH OVERLAPPING RUNS" Acta mathematica Universitatis Comenianae , v.LXXXVII , 2019 Citation Details
Baird, Molly and Billey, Sara and Demaine, Erik and Demaine, Martin and Eppstein, David and Fekete, Sándor and Gordon, Graham and Griffin, Sean and Mitchell, Joseph and Swanson, Joshua "Existence and Hardness of Conveyor Belts" The Electronic Journal of Combinatorics , v.27 , 2020 https://doi.org/10.37236/9782 Citation Details
Billey, Sara C. and Konvalinka, Matja and Swanson, Joshua P. "Asymptotic normality of the major index on standard tableaux" Advances in Applied Mathematics , v.113 , 2020 https://doi.org/10.1016/j.aam.2019.101972 Citation Details
Billey, Sara C. and Konvalinka, Matja and Swanson, Joshua P. "Tableau posets and the fake degrees of coinvariant algebras" Advances in Mathematics , v.371 , 2020 https://doi.org/10.1016/j.aim.2020.107252 Citation Details
Billey, Sara C. and Rhoades, Brendon and Tewari, Vasu "Boolean Product Polynomials, Schur Positivity, and Chern Plethysm" International Mathematics Research Notices , 2019 https://doi.org/10.1093/imrn/rnz261 Citation Details
Billey, Sara C. and Swanson, Joshua P. "The metric space of limit laws for $q$-hook formulas" Combinatorial Theory , v.2 , 2022 https://doi.org/10.5070/C62257868 Citation Details
Billey, Sara C. and Weaver, Jordan E. "A Pattern Avoidance Characterization for Smoothness of Positroid Varieties" Séminaire lotharingien de combinatoire , v.86 , 2022 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

The PI and collaborators have extensively studied asymptoticdistributions related to the descent statistic for standard Youngtableux, semistandard tableaux, and forests.  This direction lead usto define and develop the cyclotomic generating functions or CGFs.The CGF's include many famous polynomials in the liturature includingHilbert series of Cohen-Macalay rings, q-analogs of alternating signmatrices, and the length generating functions of Weyl groups.


The PI has been conduting research on positroid varieties with JordanWeaver. Positroids are certain representable matroids originallystudied by Postnikov in connection with the totally nonnegativeGrassmannian and now used widely in algebraic combinatorics.  Thepositroids give rise to determinantal equations defining positroidvarieties as subvarieties of the Grassmannian variety. Rietsch,Knutson-Lam-Speyer, and Pawlowski studied geometric and cohomologicalproperties of these varieties.  In this direction, we studiedthe geometric properties of positroid varieties by establishingseveral equivalent conditions characterizing smooth positroidvarieties using a variation of pattern avoidance defined on decoratedpermutations, which are in bijection with positroids.  This allows usto give two formulas for counting the number of smooth positroidsalong with two $q$-analogs.  Furthermore, we give a combinatorialmethod for determining the dimension of the tangent space of apositroid variety at key points using an induced subgraph of theJohnson graph.  We also give a Bruhat interval characterization ofpositroids.   An extended abstract on this work was accepted to FPSAC2022 in India as a talk, which is a high honor in our field. 

Eight papers have been published and two more submitted.  Eightgraduate students and 12 undergraduates have been mentored by the PIin research in mathematics.  The PI works to increase diversity in themathematical workforce through mentoring.


Last Modified: 01/24/2024
Modified by: Sara C Billey

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