# Robbie Angarone

Here I am at the Bean... symmetry is a major interest of mine.

My name is Robert Angarone, but you can call me Robbie.

I'm a fourth-year PhD student in the school of mathematics at the University of Minnesota and a visiting instructor at Macalester College. My advisor is Pasha Pylyavskyy. My primary research area is algebraic combinatorics. I especially enjoy representation theory, symmetric functions, total positivity, matroids, and unimodal/log-concave/real-rooted sequences.

Before coming to the University of Minnesota, I majored in math and philosophy at Macalester College. While there, I wrote an honors thesis concerning some objects in bijection with totally symmetric self-complementary plane partitions. Andrew Beveridge was my advisor. These objects (and their ilk, which are all enumerated by this wonderful sequence) are still very close to my heart.

My email is angar017 (at) umn (dot) edu.

# Research

Papers

Superspace coinvariants and hyperplane arrangements, arXiv preprint. Joint work with with Patty Commins, Trevor Karn, Satoshi Murai, and Brendon Rhoades.

Chow Rings of Matroids as Permutation Representations, arXiv preprint. Joint work with Anastasia Nathanson and Vic Reiner (arXiv preprint).

# Teaching and Mentorship

Teaching: This semester, I am a visiting instructor at Macalester College, teaching two sections of MATH 279: Discrete Mathematics. If you are a student in one of these sections, please see our course Moodle page for more information.

In previous semesters, I have taught the following courses at UMN:

Fall 2023: MATH 1241: Calculus and Dynamical Systems in Biology, TA.

Spring 2023: MATH 1051: Precalculus 1 and MATH 1031: College Algebra and Probability, TA.

Fall 2022: MATH 1051: Precalculus 1, lead instructor.

Spring 2022, Fall 2021: MATH 3283W: Sequences, series, and foundations, TA.

Spring 2021: MATH 1272: Calculus 2, TA.

Fall 2020: MATH 1271: Calculus 1, TA.

REU: In the summers of 2022 and 2023, I was a TA for the Minnesota combinatorics REU. Students in my group authored this paper.

DRP: I have been a mentor for Minnesota's DRP program several times. I have mentored projects on partition theory/Rogers-Ramanujan identities, surreal numbers, and the theory of gambling and game theory. Interested Minnesota undergraduates should apply through the DRP website.

# Talks

May 2024: Cylindrical Networks and Total Positivity, at the Graduate Online Combinatorics Colloquium. Recording of talk.

November 2022, March 2023, November 2023: Weakly Interlacing Polynomials and Total Nonnegativity, versions at my UMN preliminary oral exam presentation, at GSCC 2023, and at the UMN Combinatorics Seminar.

October 2023: Totally nonnegative matrices and real-rooted polynomials in combinatorics, expository talk at the UMN Student Combinatorics and Algebra Seminar.

January, February 2023: Permutation actions on Chow rings of matroids, versions at both the UMN Combinatorics Seminar and MaTroCom. Abstract.

November 2022, March 2023: Weakly Interlacing Polynomials and Total Nonnegativity, versions for both my UMN preliminary oral exam presentation and at GSCC 2023.

September 2022: Immanants imminent!, 5-minute expository "lightning talk" at the UMN Student Combinatorics and Algebra Seminar.

February 2022: Total positivity in three flavors, expository talk at the UMN Student Combinatorics and Algebra Seminar. Abstract.

July 2021: Characters of the infinite symmetric group and total positivity, expository talk at the UMN Student Summer Representation Theory Seminar. Abstract (scroll down to my name), notes.

April 2020: Stacking Blocks: Natural bijections via triangular families, Macalester College honors thesis defense. Slides (click 'present').

February 2020: Building Bridges: Finding natural plane partition bijections, Macalester College capstone project presentation. Slides (click 'present').

# Activities

In the summer of 2024, I look forward to participating in the AlCoVR Workshop on Dynamical Algebraic Combinatorics, which is one of (perhaps the) first math conferences to take place entirely in virtual reality. I will also attend FPSAC and the Summer School in Algebraic Combinatorics at MPI Leipzig.

In the Spring of 2024, I participated in the CAAC conference.

In the Summer of 2023, I organized the 2023 Student Summer Representation Theory Seminar with fellow graduate student Carolyn Stephen. I participated in an AIM workshop on total positivity. I also participated in MRWAC, a Minnesota combinatorics research workshop.

In Spring 2023, I attended and presented at GSCC 2023 in St Louis, a combinatorics conference organized for and by graduate students.

In Winter 2023, I participated in the Workshop on Matroids and Tropical Combinatorics in London; I also gave a presentation there.

In Fall 2022, I passed my preliminary oral exam with a presentation titled "Weakly Interlacing Polynomials and Total Nonnegativity."

In Summer 2022, I participated in the Summer School in Algebraic Combinatorics in Kraków. I also helped to organize a combinatorics research workshop with fellow graduate students Sylvester Zhang and Trevor Karn.

In the 2021-2022 school year, I helped to organize UMN's Student Combinatorics and Algebra Seminar. The current website is here.

# Misc.

You might be looking for my father, Robert Angarone, or Robert Angarone (no relation).

I believe in (and I am doing my best to uphold) the axioms enumerated by Federico Ardila. I signed Math Boycotts Police.

The header and footer of this page are 25.15 from Serie 25: Fuerza Nuclear Fuerte by Eduardo Terrazas.

I am in the process of collecting every album, EP, and single (in every format) released by harpist Joanna Newsom. If you own an original CD copy of 2002's Walnut Whales, I will buy it from you. As of October 2023, I am happy to share that my collection is complete!

## Littlewood and Richardson visited the French art museum. Littlewood remarked, disappointed, that one of the newest paintings was only slightly interesting, and rather typical.

“Indeed,” replied Richardson, “a semi standard young tableaux.”