Ramanujan and Expander Graphs

Series
Stelson Lecture Series
Time
Thursday, October 24, 2024 - 4:30pm for 1 hour (actually 50 minutes)
Location
Bill Moore Student Success Center, Press Rooms A & B
Speaker
Peter Sarnak – Princeton University – sarnak@math.princeton.eduhttps://www.math.princeton.edu/people/peter-sarnak
Organizer
Alex Dunn

Expander graphs are highly connected sparse graphs. They have wide theoretical and practical applications in Computer Science and Engineering. Ramanujan Graphs are optimal expanders and as the name suggests they are constructed number theoretically. We review their construction as well more recent constructions that use statistical physics. We highlight some recent applications in the reverse direction where combinatorial ideas are combined with arithmetical ones to establish expansion of graphs arising in diophantine analysis.