[cmath] Alex Lubotzky's talk at Western/April 20th/ 4:45 p.m. EST /MC 107 + Z00M link

[Jan Minac]

Dear Colleagues,

It is a great pleasure for me and my colleagues at Western to share with
you Professor Alex Lubotzky's talk with details below. Alex work with his
collaborators is extremely interesting and Alex is a fantastic speaker with
capabilty
of explaining mathematics in a friendly and engaging manner.

With very best wishes to you all,

Ján
*********************
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> Western Academy Visiting Fellow *Dr. Alex Lubotzky* (Weizmann Institute
> of Science- http://www.ma.huji.ac.il/~alexlub) see also (
> https://en.wikipedia.org/wiki/Alexander_Lubotzky) will be delivering a
> talk relating to his latest research.
>
> Dr. Lubotzky completed his PhD under the supervision of Hillel Furstenberg
> (2020 Abel Prize) and has made foundational contributions in modern
> mathematics, ranging from Galois theory, group theory to number theory and
> graph theory. He is also one of the founders of the study of Ramanujan
> graphs.
>
> The talk will be hybrid and will take place on *Thursday, April 20, 2023*
> in
> University of Western Ontario
> Middlesex College (MC)
> MC107, 4 :45 - 5:45 p.m (Eastern time zone)
>
> To join remotely, please use the following zoom link:
>
> https://westernuniversity.zoom.us/j/96923989092
>
> Please find the abstract and title below:
>
>
> *Good locally testable codes*
> An error-correcting code is locally testable (LTC) if there is a random
> tester that reads only a small number of bits of a given word and decides
> whether the word is in the code, or at least close to it. A long-standing
> problem asks if there exists such a code that also satisfies the golden
> standards of coding theory: constant rate and constant distance. Unlike the
> classical situation in coding theory, random codes are not LTC, so this
> problem is a challenge of a new kind.
>
> We construct such codes based on what we call (Ramanujan) Left/Right
> Cayley square complexes.  These objects seem to be of independent
> group-theoretic interest. The codes built on them are 2-dimensional
> versions of the expander codes constructed by Sipser and Spielman (1996).
> The main result and lecture will be self-contained. But we hope also to
> explain how the seminal work of Howard Garland ( 1972) on the cohomology of
> quotients of the Bruhat-Tits buildings of p-adic Lie group has led to this
> construction ( even though it is not used at the end).
>
> Based on joint work with I. Dinur, S. Evra, R. Livne, and S. Mozes.
>
>> *********************************************
>>
>> Ján Mináč
>> Western University
>> Department of Mathematics
>> Middlesex College, Room 131
>> London, Ontario, Canada N6A 5B7
>> https://www.math.uwo.ca/faculty/minac/
>>
>
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