SageDays 129

This workshop will focus on (algebraic) combinatorics, broadly interpreted, and will take place after FPSAC 2025. We will also have tutorials for beginners and time for coding sprints.

More information will be made available soon.

Dates

August 4-6, 2025

Venue

Hokkaido University Science Building 4 room 4-501 (5th floor)

Details

To register, please email Travis Scrimshaw tcscrims <at> gmail.com with your name and affiliation. There is no registration fee.

If you are interested in giving a talk, please indicate so in your registration email.

Schedule

A coding sprint is a time to work on code. During these periods, since we will have no talks, participants can use this as breaks.

The conference will officially begin Monday 14:00 (JST), but the room will be available before that for additional coding sprints and discussions.

Titles / Abstracts

SageMath Tutorial notebook

Combinatorial Tutorial notebook

Darij Grinberg

Title: Five questions on symmetric group algebras

Abstract: I will present (at least) five open problems on symmetric group algebras, as well as some of their context. The Young--Jucys--Murphy elements, the Murphy cellular bases, and the Specht modules will all be touched upon.

slides

Benjamin Hackl

Title: Moving Fast Without Breaking Things: How to Create and Maintain your own Sage (Python) Packages

Abstract: With the rise of FAIR (Findable — Accessible — Interoperable — Reusable) software practices, it is becoming more and more important to think about the practice of sharing your code and computations such that your results are easy to reproduce by others. In this workshop we will explore a hand full of useful tools and practices that intend to make this task a bit easier for you. In particular, we will discuss

• the clean separation of your code into “calculations” and “the rest”,
• setting up a proper Python project that is ready to be distributed,
• documentation and testing,

• and helpful software infrastructure (via GitHub) for automating the “boring part”.

slides

Andrew Luo

Title: A SageMath Package for Analytic Combinatorics in Several Variables

Abstract: Analytic Combinatorics in Several Variables (ACSV) is a branch of mathematics concerned with the asymptotic behaviour of sequences derived from their multivariate generating functions, and has applications ranging from the analysis of data structures to bioinformatics, algebraic statistics, and queuing theory. While ACSV adapts techniques from a wide range of mathemetical topics including multivariate complex analysis, algebraic geometry, and stratified Morse theory, computer algebra systems can be used to automate much of the theory. We present the sage-acsv package which, under certain niceness conditions, can rigorously compute the asymptotic behaviour of sequences given its multivariate generating function. We extensively use Sage's built-in Polynomial Rings and Algebraic Numbers structures and various algorithms from commutative algebra to perform our computations. Our package aims to increase the accessibility of the theory of ACSV for researchers and demonstrates an interesting and practical use-case of the SageMath software.

slides notebook

Martin Rubey

Title: Being Lazy

Abstract: I will demonstrate some of the abilities of the lazy formal series framework in SageMath. In particular, the code enables us to compute with power series, Dirichlet series, symmetric functions and combinatorial species. I will focus on the possibility to define series implicitly, which is a novel feature.

I will also discuss some open problems, involving permutation groups, plethysm but also plain coding.

slides

Attendees

Speakers

• Darij Grinberg (Drexel University)

• Benjamin Hackl (University of Graz)

• Andrew Luo (University of Waterloo)

• Martin Rubey (TU Wien)

• Travis Scrimshaw (Hokkaido University)

Participants

• Ryo Kato (Tsukuba University)

• Jianrong Li (University of Vienna)

• Jun Murakami (Waseda University)

• Hiroshi Naruse (University of Yamanashi)

• Duc-Khanh Nguyen (Okinawa Institute of Science and Technology)

• Hiroyuki Ochiai (九州大学　マス・フォア・インダストリ研究所)

• Yasuhide Numata (Hokkaido University)

• Kazuma Sakamoto (Hokkaido University)
• Yuto Shimoda (Hokkaido University)

Organizers

Travis Scrimshaw (Hokkaido University)