COSE – CULT

COmbinatorics Seminar for Everyone (COSE)

This is a reading seminar open to everyone, especially bachelor, master and PhD students. The topic changes every year/semester. It includes free coffee breaks.

If you are interested in participating, please send an email to cult-owner@lists.dm.unipi.it, bring your coffee cup/mug/water bottle, and be ready to give a talk!

2024-2025

In the first semester of this year the topic of the seminar is "Sandpile model". We will follow mainly the book by Corry and Perkinson.

[CP] Divisors and Sandpiles: An Introduction to Chip-Firing, 2010

DATE	TIME	ROOM	SPEAKER	TITLE	REFERENCES
03/10/2024	11:00-13:00	Aula seminari	Michele D'Adderio	Introduction to the dollar game	[CP] Sections 1.1 and 1.2
17/10/2024	11:00-13:00	Aula seminari	Cristofer Villani	Picard and Jacobian groups. Discrete Laplacian.	[CP] Sections 1.3 and 2.1
31/10/2024	11:00-13:00	Aula seminari	Pietro Gualdi	Reduced Laplacian and structure of Picard group	[CP] Sections 2.2 and 2.4
14/11/2024	11:00-13:00	Aula seminari	Simone Foti	Complete linear systems and a greedy algorithm	[CP] Sections 2.3 and 3.1
28/11/2024	11:00-13:00	Aula seminari	Roberto Maria Tocco	q-reduced divisors and superstable configurations	[CP] Sections 3.2 and 3.3
12/12/2024	11:00-13:00	Aula seminari	Lorenzo Noè	Dhar's burning algorithm and the debt-reduction trick	[CP] Section 3.4

2023-2024

In the second semester of this year the topic of the seminar is "Hyperplane arrangements". We will follow mainly the lecture notes by Richard Stanley:

[Stanley] Stanley, "An introduction fo Hyperplane arrangements", 2006

DATE	TIME	ROOM	SPEAKER	TITLE	REFERENCES
28/02/2024	11:00-13:00	Saletta riunioni	Michele D'Adderio	Introduction to hyperplane arrangements	[Stanley] Lecture 1
13/03/2024	11:00-13:00	Sala riunioni	Giulia Codenotti	Characteristic polynomial and Moebius function	[Stanley] Lecture 1
27/03/2024	11:00-13:00	Sala riunioni	Sabrina Botticchio	Crosscut theorem, Whitney's theorem, deletion-restriction of the characteristic polynomial of an arrangement	[Stanley] Lecture 2, Section 2.1
10/04/2024	11:00-13:00	Sala riunioni	Alessio Sgubin	Zaslavsky theorem via deletion restriction and via Euler characteristic	[Stanley] Lecture 2, Section 2.2
30/04/2024	11:00-13:00	Sala riunioni	Alessandro Tedeschi	Graphic arrangements	[Stanley] Lecture 2, Section 2.3
15/05/2024	11:00-13:00	Sala riunioni	Lorenzo Noé	Matroids, Tutte polynomial and arrangements	[Stanley] Lecture 3

In the first semester of this year the topic of the seminar is "Matroids". We will follow mainly the lecture notes by Vic Reiner:

[Reiner] Reiner, "Lectures on matroids and oriented matroids", 2005

Date	Time	Room	Speaker	Title	References
04/10/2023	11:00-13:00	Aula seminari	Michele D'Adderio	Introduction to matroids	[Reiner] Lecture 1
18/10/2023	11:00-13:00	Aula seminari	Alessandro Tedeschi	Birkhoff theorem on the poset of flats of a matroid	[Reiner] Lecture 1
25/10/2023	11:00-13:00	Aula seminari	Alessio Sgubin	Introduction to oriented matroids	[Reiner] Lecture 1
15/11/2023	11:00-13:00	Aula seminari	Luca Vantaggio	Matroids, greedy algorithm, direct sum, deletion and contraction	[Reiner] Lectures 1 and 2
29/11/2023	11:00-13:00	Aula seminari	Giovanni Interdonato	Duality and representability of matroids	[Reiner] Lecture 2
13/12/2023	11:00-13:00	Aula seminari	Roberto Riccardi	Realizability of oriented matroids and zonotopes	[Reiner] Lecture 2

2022-2023

Date	Time	Room	Speaker	Title	References
04/10/2022	11:00-13:00	Aula seminari	Michele D'Adderio	Introduction to COSE 2022-2023	[BS] Chapter 1
25/10/2022	11:00-13:00	Aula seminari	Matteo Poletto	Introduction to posets. First reciprocity theorem.	[BS] Chapter 2
08/11/2022	11:00-13:00	Aula seminari	Matteo Migliorini	Introduction to polytopal geometry.	[BS] Chapter 3, Sections 3.1, 3.2, 3.3.
22/11/2022	11:00-13:00	Aula seminari	Alessandro Tedeschi	Face poset and Euler characteristic.	[BS] Chapter 3, Sections 3.3, 3.4.
06/12/2022	11:00-13:00	Aula seminari	Alessio Sgubin	Moebius functions and Zaslavsky's theorem	[BS] Chapter 3, Sections 3.5, 3.6.
09/03/2022	11:00-13:00	Aula riunioni	Matteo Palmieri	The Brianchon-Gram Relation	[BS] Chapter 3, Section 3.7.
23/03/2022	11:00-13:00	Aula riunioni	Philippe Nadeau	Combinatorial reciprocity for chromatic polynomials	https://arxiv.org/abs/1904.01262
06/04/2022	11:00-13:00	Aula riunioni	Giovanni Interdonato	Generating functions and quasipolynomials	[BS] Chapter 4, Sections 4.1-4.5.
20/04/2022	11:00-13:00	Aula riunioni	Davide Chionna	Reciprocity for rational simplices	[BS] Chapter 4, Sections 4.6-4.7.
04/05/2022	11:00-13:00	Aula riunioni	Federico Lazzeri	Reciprocity for simplicial cones	[BS] Chapter 4, Section 4.8.
18/05/2022	11:00-13:00	Aula riunioni	Roberto Riccardi	Chain partitions and recirpocity	[BS] Chapter 4, Section 4.9.
25/05/2022	11:00-13:00	Aula riunioni	Lucio Tanzini	Subdivisions and Ehrhart-Macdonald reciprocity	[BS] Chapter 5, Sections 5.1-5.2.

COmbinatorics Seminar for Everyone (COSE)​

COmbinatorics Seminar for Everyone (COSE)