Sage Days 116
Dates
 Dec 2730, 2022
Venue
Sol Beach, Yangyang, South Korea
 Lecture Hall: Hotel building (Tower A), first floor, Sapphire II
Organizing Committee
 Meesue Yoo, Chair (Chungbuk National University)
JiSun Huh (Ajou University)
 Jang Soo Kim (Sungkyunkwan University)
Plenary Speakers
 Yasuhide Numata (Hokkaido University)
 Travis Scrimshaw (Hokkaido University)
 Heesung Shin (Inha University)
Invited Speakers
 Meesue Yoo (Chungbuk National University)
 Eunjeong Lee (Chungbuk National University)
 Taehyeok Heo (Seoul National University)
 Seung Jin Lee (Seoul National University)
Software demo
 Jang Soo Kim (Sungkyunkwan University)
Schedule
time 
27 Tue 
28 Wed 
29 Thu 
30 Fri 
07:3008:50 

Breakfast 
Breakfast 
Breakfast 
08:5010:00 

Early bird coding 
Early bird coding 
Early bird coding 
10:0011:00 

Yasuhide Numata 1 
Travis Scrimshaw 1 
Progress report 
11:0012:00 

Yasuhide Numata 2 
Travis Scrimshaw 2 
Farewell 
12:0014:00 

Lunch 
Lunch 

14:0015:00 
Opening 
Jang Soo Kim 
Coding & exercise 

15:0015:30 
Meesue Yoo 
Useful tools 
Coding & exercise 

15:3016:00 
Eunjeong Lee 
Useful tools 
Coding & exercise 

16:0016:30 
Taehyeok Heo 
Problem session 
Coding & exercise 

16:3017:00 
Seung Jin Lee 
Problem session 
Coding & exercise 

17:3019:00 
Dinner 
Dinner 
Dinner 

19:0020:00 
Heesung Shin 1 
Heesung Shin 3 


20:0021:00 
Heesung Shin 2 
Pro Code 101 
Torus Tournament 

Abstracts
Plenary Talks
 Yasuhide Numata (Hokkaido University)
 Talk 1
 Title: On data structures of Python/Sage.
 Abstract: First, I will introduce fundamental data structures of Python. Roughly speaking, Sage is Python with additional structures. The original data structures of Python can be used in Sage, too. Some of them are, however, overwritten. We see the difference between Python and Sage.
 Talk 2
 Title: How to use classes as user of Sage.
 Abstract: First, we see basic syntax to define a new class in Python. Then I will introduce how to extend some class as a user of Sage.
 Project(s)
Make Korean quick references (Level: For newbie): We have quick references [1], i.e., cheatsheets. Almost of them are distributed with GFDL, and some of them are translated into some languages. We, however, have no Korean version. So translate them into Korean, or make a new reference for your research topics. [1] https://wiki.sagemath.org/quickref
 Talk 1
 Travis Scrimshaw (Hokkaido University)
 Talk 1
Title: The details of contributing to SageMath
Abstract: In this talk, we will discuss how to prepare your code for inclusion into SageMath. These include things such as: (1) how to find the right place to put your code; (2) formatting your code, e.g., PEP8; (3) writing (good) documentation and doctests. Additionally, we will look at the current development model for SageMath and go through the contribution process. Lastly, we see what will change with the upcoming transition to GitHub's model.
 Talk 2
Title: Getting the full potential from SageMath
Abstract: SageMath is built from numerous open source packages, but there are additional packages that are not installed by default (optional/experimental packages) and those further built on top of Sage (downstream packages). We will discuss some of these packages and how to install them from a source build, and highlight some of them and how they expand the computational abilities of SageMath (with the speaker's bias). Furthermore, not every feature of these packages (such as GAP) are immediately accessible in SageMath. We discuss how to access some of these packages within SageMath and leverage some of their more advanced capabilities (which make for good things to contribute to SageMath).
 Projects
Implement representations of simple Lie algebras. lie_algebra_reprs.sage
Implement qcharacters by the FrenkelMuhkin algorithm. q_characters.sage
 Implement q,tcharacters for simplylaced types using Nakajima's or Hernandez's algorithm.
 Implement (dual) Grothendieck polynomials.
Implement Specht modules for the symmetric group. specht_modules.sage
 Implement type C Fock space and the corresponding global crystal basis.
Implement the cactus group by using https://arxiv.org/abs/2202.00860.
 Implement G(r,p,n) as a subgroup of the colored permutation group.
 Implement the type q crystal structure on shifted tableaux (see, e.g., Assaf and Oguz) and reduced factorizations (see Marberg).
Implement the qcommuting Laurent polynomials https://trac.sagemath.org/ticket/34472
 Implement the Coxeter complex for finite Coxeter groups. (Bonus: the Milnor fiber complex of finite reflection groups; defined in the same way by cosets.)
 Talk 1
 Heesung Shin (Inha University)
 Sage Tutorial 1
 Title: Sage as a Calculator
Abstract: In the first tutorial, we will look at some simple SageMath commands that can be used like a calculator.
 Sage Tutorial 2
 Title: Analysis and Algebra
Abstract: In the second tutorial, we will practice SageMath commands that are often used in analysis and algebra.
 Sage Tutorial 3
See also: https://ensual.github.io
 Sage Tutorial 1
Invited Talks
 Meesue Yoo (Chungbuk National University)
 Title: Enumeration of standard barely setvalued tableaux of shifted shapes
 Abstract: In this work, we prove the CDE property of the trapezoidal shifted shapes by counting standard barely setvalued tableaux via qintegral method. A standard barely setvalued tableau of shape λ is a filling of the Young diagram λ with integers 1,2,...,λ+1 such that the integers are increasing in each row and column, and every cell contains one integer except one cell that contains two integers. Counting standard barely setvalued tableaux is closely related to proving Young's lattice has the coincidental downdegree expectations (CDE) property. Using qintegral techniques we give a formula for the number of standard barely setvalued tableaux of arbitrary shifted shapes. We then prove a conjecture of Reiner, Tenner and Yong on the CDE property of trapezoidal shifted shape (n,n2,...,n2k). This work was initiated in Sage Days held in Slovenia, generalizing Sam Hopkins' work presented in Fpsac held a week before. This workshop might be the right place to present the result. This is joint work with Jang Soo Kim and Michael Schlosser.
 Eunjeong Lee (Chungbuk National University)
 Title: On toric varieties in the flag variety
 Abstract: Let G be a simple Lie group and let B be a Borel subgroup. The homogeneous space G/B becomes a smooth projective variety called the flag variety. The flag variety provides an interesting connection between geometry, topology, representation theory, and combinatorics as is exhibited in the BorelWeilBott theorem, Schubert calculus, and so on. A maximal (complex) torus T acts on the flag variety and there are lots of toric varieties with respect to this torus action. Indeed, the Torbit closure of a point in the flag variety is always a toric variety. One can produce toric Schubert varieties and toric Richardson varieties in this way. In this talk, we study toric varieties in the flag variety, especially certain smooth toric Richardson varieties containing toric varieties of Catalan type and toric Schubert varieties. This talk is based on joint work with Mikiya Masuda and Seonjeong Park.
 Taehyeok Heo (Seoul National University)
 Title: The crystal structure of King tableaux
 Abstract: The King tableau is a symplectic generalization of semistandard tableaux, which describes irreducible modules over symplectic Lie algebras. Whereas it is a very wellknown object in combinatorics, its crystal structure is not, but Lee recently explains its crystal structure via oscillating tableaux. In this talk, I will briefly explain the crystal structure of King tableaux. This talk is a review of Lee's article (arXiv:1910.04459).
 Seung Jin Lee (Seoul National University)
 Title: Rook placements and chromatic quasisymmetric functions
 Abstract: In this talk, we describe two types of rook placements, arising from the HallLittlewood expansion and eexpansion of chromatic quasisymmetric functions. I will describe the relationship between these rook placements and discuss how Sage can help us to understand the relationship.
Software demo
 Jang Soo Kim (Sungkyunkwan University)
 Title: Introduction to Newbiemacs
 Abstract: Newbiemacs is a preconfigured GNU Emacs distribution inspired by Spacemacs. Newbiemacs is desiged for mathematician who are new to Emacs. In this talk we will see basic features of Newbiemacs, for example, how to manage pdf and tex files, and how to organize notes using orgmode.
Newbiemacs Home: https://jangsookim.github.io/newbiemacs/newbiemacshome.html
Some Sage Code
Torus Tournament
 goinmul
 jisun : winner!
 jang soo
 intermediate
 jihyeug : winner!
 newbie
 akito : winner!
 seung jin
 minho
 heesung
 yas
 dongjune
 scores
division 
name 
scores 
level 
goinmul 
jia 
424800 
15 
intermediate 
jihyeug 
152700 
8 
goinmul 
jangsoo 
152100 
8 
newbie 
uraki 
144300 
8 
newbie 
SJ 
90600 
6 
newbie 
mh 
49800 
4 
newbie 
heesung 
44100 
4 
newbie 
dongjun 
42900 
4 
newbie 
yas 
19800 
2 