On an inverse electrodynamic problem

The inverse electrodynamic problem of determining the electric conductivity of a metal sample from a measured resulting outside field and a given applied field is considered. It is shown that the corresponding operator equation is not uniquely solvable in the general case of magnetic and nonmagnetic metals. In the latter case, the additive class of nonuniqueness is described exactly; i.e., the kernel of the integro-differential operator is found.