Infinite families of regular expanders of arbitrary constant degree obtained via the modified zig-zag product

Abstract

We generalize the zig-zag product construction to produce infinite families of regular graphs of any constant degree. We analyze the second largest eigenvalue of this new zig-zag product to show that the modified zig-zag product of good expanders is again a good expander (yet not Ramanujan).

arXiv commentPaper withdrawn due to error in main theorem