Communicated by P. Colli
SUMMARYWe consider an inverse problem to recover a space-and time-dependent relaxation function of heat ux in a three-dimensional body on the basis of the restriction of the Dirichlet-to-Neumann operator of the related equation of heat ow onto a set of Dirichlet data of the form of a product of a ÿxed timedependent coe cient and a free space-dependent function. Uniqueness of the solution of this inverse problem is proved.