Spectral techniques for expander codes and generalized cyclic codes
We show that spectral techniques can be used to encode the explicit expander codes constructed by Sipser and Spielman (see IEEE Trans. on Information Theory, vol.42, no.6, p.1710-22, 1996) . These codes can be viewed as generalized cyclic codes for certain non-abelian groups. Many of the classical spectral techniques for cyclic codes extend to this general setting.