Guilherme Zeus
Dantas e Moura
Master of Mathematics Student
Department of Combinatorics & Optimization
University of Waterloo
200 University Ave W, Waterloo, Ontario, Canada N2L 3G1
Office: MC 6311
Email:
zdantase@uwaterloo.ca
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zeus@guilhermezeus.com
I will start my doctoral studies in the Department of Combinatorics & Optimization at the University of Waterloo under the supervision of Olya Mandelshtam on 2026-01. I am completing my Master of Mathematics degree in the same department on 2025-12, also supervised by Olya Mandelshtam, where I worked on permuted-basement non-symmetric Macdonald polynomials. My research interests are in combinatorics, particularly algebraic and bijective combinatorics.
Before Waterloo, I completed my Bachelor of Science degree at Haverford College in 2024-05, with majors in Mathematics and Linguistics. As a high school student, I was an IMO medalist. My Erdős number is two. My non-research interests include math olympiads, board games, linguistics, and Linux.
My family name is “Dantas e Moura”, so I should be listed as “Dantas e Moura, Guilherme Zeus” (not “Moura”). Please use “D” as the surname initial.
Recent Publications (all)
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Deterministic and Probabilistic Bijective Combinatorics for Macdonald Polynomials (2025)
Master's thesis for a degree in Combinatorics and Optimization at the University of WaterlooAbstract
Permuted-basement Macdonald polynomials $E^\sigma_\alpha(\mathbf{x}; q, t)$ are nonsymmetric generalizations of symmetric Macdonald polynomials indexed by a composition $\alpha$ and a permutation $\sigma$. They form a basis for the polynomial ring $\mathbb{Q}(q, t)[\mathbf{x}]$ for each fixed permutation $\sigma$. They can be described combinatorially as generating functions over augmented fillings of composition shape $\alpha$ with a basement permutation $\sigma$.
We construct deterministic bijections and probabilistic bijections on fillings that prove identities relating $E^\sigma_\alpha$, $E^{\sigma s_i}_\alpha$, $E^\sigma_{s_i \alpha}$, and $E^{\sigma s_i}_{s_i \alpha}$. These identities correspond to two combinatorial operations on the shape and basement of the fillings: swapping adjacent parts in the shape, which expands $E^\sigma_\alpha$ in terms of $E^\sigma_{s_i \alpha}$ and $E^{\sigma s_i}_{s_i \alpha}$; and swapping adjacent entries in the basement, which gives $E^\sigma_\alpha = E^{\sigma s_i}_\alpha$ when $\alpha_i = \alpha_{i+1}$.
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Probabilistic Entry Swapping Bijections for Non-Attacking Fillings (2025)
Abstract
Non-attacking fillings are combinatorial objects central to the theory of Macdonald polynomials. A probabilistic bijection for partition-shaped non-attacking fillings was introduced by Mandelshtam (2024) to prove a compact formula for symmetric Macdonald polynomials. In this work, we generalize this probabilistic bijection to composition-shaped non-attacking fillings. As an application, we provide a bijective proof to extend a symmetry theorem for permuted-basement Macdonald polynomials established by Alexandersson (2019), proving a version with fewer assumptions.
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Algebraic Combinatorics, Volume 8 (2025) no. 4, pp. 997–1019Abstract
Laurent Phenomenon algebras, first introduced by Lam and Pylyavskyy, are a generalization of cluster algebras that still possess many salient features of cluster algebras. Graph Laurent Phenomenon algebras, defined by Lam and Pylyavskyy, are a subclass of Laurent Phenomenon algebras whose structure is given by the data of a directed graph. The main result of this paper is that the cluster monomials of a graph Laurent Phenomenon algebra form a linear basis, conjectured by Lam and Pylyavskyy and analogous to a result for cluster algebras by Caldero and Keller.
Recent and Upcoming Activities (all)
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I will attend the Combinatorial Algebra meets Algebraic Combinatorics (CAAC) conference at Dalhousie University from 2026-01-23 to 2026-01-25.
I will present a poster on Probabilistic Bijections on Nonattacking Fillings. -
I will present a talk on my graduate reseach as part of the Young Academic Alumni Lecture Series at Haverford College on 2026-02-03 at 4:30 PM.
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I attend the weekly Algebraic and Enumerative Combinatorics Seminar at the University of Waterloo.