Monthly Archives: May 2013

More on Expanders

We discussed expanders and their applications in the last class. Today I will cover an explicit construction by Spielman, which is simpler than the well-known combinatorial construction based on the zigzag  product by Reingold, Vadhan and Wigderson.

Here’s a series of two talks by Avi Wigderson explaining much more about the applications of expanders and also the zigzag construction if you are interested:



Higher-Order Cheeger Inequalities

We discussed Cheeger’s inequality in the last lecture and I briefly mentioned some generalizations to higher eigenvalues. Here is a nice talk by Luca Trevisan giving some intuition for one of the generalizations I mentioned:

The talk is very accessible and does not assume any background in spectral graph theory.