The seriation problem in the presence of a double Fiedler value

Seriation is a problem consisting of seeking the best enumeration order set units whose interrelationship described by bipartite graph. An algorithm for spectral seriation based on use Fiedler vector Laplacian matrix associated to was developed Atkins et al. under assumption that value simple. In this paper, we analyze case in which not simple, discuss its effect admissible solutions, and study possible approaches actually perform computation. Examples numerical experiments illustrate effectiveness proposed methods.