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<font face="Tahoma" size="2"><b>From:</b> noreply+automations@airtableemail.com <noreply+automations@airtableemail.com>On Behalf OfTheoryBot (via Airtable) <noreply+automations@airtableemail.com><br>
<b>Sent:</b> Wednesday, March 22, 2023 12:43:18 AM (UTC-06:00) Central Time (US & Canada)<br>
<b>To:</b> Antares Chen <antaresc@uchicago.edu><br>
<b>Cc:</b> Christopher Kang <ctkang@uchicago.edu><br>
<b>Subject:</b> Theory Lunch 2023-03-22T17:30:00.000Z<br>
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<p style="margin-top:0"><span>Today's Theory Lunch talk:</span></p>
<p><em><span>Tushant Mittal (University of Chicago): Meeting Ramanujan, well almost!</span></em></p>
<p><span><a href="https://urldefense.com/v3/__https://uchicago.zoom.us/j/91616319229?pwd=dDdXQnFXeGNubFRkZy9hTDQrcWlXdz09__;!!BpyFHLRN4TMTrA!7RDk1m844JpCxiHNrCPuSz0m2FJkOUHJTaaQp2LKhAIklpP1eZZ0rXTt8OslMUaSjjat2w6D8fAH1oS2S_FzChI1lu1l_-PQzHE$">https://uchicago.zoom.us/j/91616319229?pwd=dDdXQnFXeGNubFRkZy9hTDQrcWlXdz09</a></span></p>
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<p><span>Description: A Ramanujan graph is a “spectrally optimal” expander, i.e., a sparse yet very-well connected graph. Optimality here, is with respect to the tug of war between the graph’s sparsity (degree) and its “well-connectedness” (spectral expansion). </span></p>
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<p><span>The problem at hand is that of amplifying a graph’s quality while preserving its structure. That is, starting from a given (poor-quality) expander, can we deterministically improve it all the way to a Ramanujan one? We show that we can almost get there
using Ta-Shma’s breakthrough technique, originally used to construct error-correcting codes. </span></p>
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<p><span>In this talk, we will introduce the notion of expanders, and, sketch out the wonderful connections between pseudorandomness, error-correction and representation theory. Based on joint work with Fernando Granha Jeronimo, Sourya Roy and Avi Wigderson.</span></p>
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<div>©2023 Airtable</div>
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