University of Cambridge > Talks.cam > Combinatorics Seminar > Expanders, Ramanujan graphs and random lifts

  Browse A-Z

Log in

University Account External (via Google)

🔐 Log In

Information on

Subscribing to talksdetails Finding a talkdetails Adding a talkdetails Disseminating talksdetails Help and Documentationdetails

ℹī¸ Information

Expanders, Ramanujan graphs and random lifts

Download to your calendar using vCal

  • UserBenny Sudakov (UCLA)
  • ClockWednesday 10 March 2010, 14:30-15:30
  • HouseMR12.

If you have a question about this talk, please contact Andrew Thomason .

Expansion of a graph is one of the most fundamental concepts in modern combinatorics, which has numerous applications in many mathematical areas. It is well known that expansion is closely relates to the spectral properties of graph. The celebrated Alon-Boppana bound says that all eigenvalues of a d-regular graph must be at least 2sqrt(d-1) – o(1) and graphs that meet this bound are called Ramanujan Graphs. There are still many unresolved questions about the existence of such graphs. In this talk we survey this background material, then we explain what lifts of graphs are and how the above questions can be approached using random lifts of graphs.

Joint work with Lubetzky and Vu.

This talk is part of the Combinatorics Seminar series.

This talk is included in these lists:

Note that ex-directory lists are not shown.

Other lists

Babraham - The Cambridge Building - The Petersfield Lecture Theatre Senior Parlour, Gonville & Caius College https://ukri.zoom.us/j/97192560202; BAS Seminar Room 330b

Other talks

Loke CTR Annual Meeting 2026 - Epigenetics of embryogenesis and placentation Seminars in Cancer Title TBC Laser tomography for wide area gas emission spatio-temporal reconstruction Title to be confirmed Tea and Coffee Break
 

Š 2006-2025 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity