The Technion Theory Lunch is a seminar run by the theory group at the Department of Computer Science, Technion. The seminar holds weekly meetings in which graduate students and faculty from the Technion and other universities in Israel and abroad present recent results or other interesting topics in theoretical computer science. The seminar is open to faculty, graduate and undergraduate students interested in theory of computing.
Wednesdays, 13:00-14:00 (food starts at 12:45)
Room 201 (note return to traditional room), Taub Building
If you are interested in giving a talk at the seminar, contact Omri Ben-Eliezer and/or David Wajc.
The seminar’s mailing list is used to announce our weekly meetings, and also to publicize CS theory related events, such as workshops and seminars, in Israel and abroad.
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Assaf Reiner (Hebrew University)
Lossless vertex expanders are d-regular (or biregular) graphs in which every small set of vertices S has almost the largest possible number of neighbors d|S|. While random regular graphs are known to be lossless expanders with high probability, constructing them explicitly has been a longstanding challenge.
In this talk, I will present the first explicit construction of constant-degree two-sided lossless vertex expanders. The resulting graphs also admit a free group action, and hence realize the new families of good quantum LDPC codes due to Lin and Hsieh. The construction is based on taking an appropriate product of a constant-sized lossless expander with a base graph constructed from LPS Ramanujan cubical complexes, which are natural high-dimensional generalizations of the well-known LPS Ramanujan graphs.
Based on joint work with Jun-Ting Hsieh, Alex Lubotzky, Sidhanth Mohanty and Rachel Zhang (FOCS 2025).
Omrit Filtser (Open University)
Upcoming
