Brandeis Combinatorics Seminar -  Fall 2025

The Brandeis Combinatorics Seminar is an introductory seminar for combinatorics.
The talks should be (at least partially) understandable to first year graduate students.

            The zoom link is  https://brandeis.zoom.us/j/94622483750

October 20: 

Speaker: Ira Gessel

Title:  Lattice paths and the Geode.

Abstract: In recent highly publicized work, Norman Wildberger and Dean Rubine studied a method for solving equations using power series. They found an interesting factorization: Let S be the power series in variables t_1, t_2, ... satisfying S = 1 + t_1 S + t_2 S^2 + .... Wildberger and Rubine showed that S-1 is divisible by t_1 + t_2 + .... They called the quotient the "Geode" and asked about its combinatorial significance. I will show that the Geode has a very simple combinatorial interpretation in terms of lattice paths.

October 27: 

Speaker: Neha Goregaokar (Brandeis)

Title:  TBD

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November 3: 

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November 10: 

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November 17: 

Speaker: Jonathan Fang (Brandeis)

Title: TBD  

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November 24: 

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December 1: 

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December 8: 

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Links to previous semesters: Spring2025 Fall2024, Spring2024, Fall2023, Spring2023, Fall 2022, Spring 2022, Fall 2021, Spring 2020, Fall 2019, Fall 2018, Spring 2018, Fall 2017, Spring 2017, Fall 2016, Spring 2016, Fall 2015, Spring 2015, Fall 2014, Spring 2014, Fall 2013.