Recovering differential operators with two retarded arguments

This paper deals with non-self-adjoint second-order Differential Operators with two constant delays τ _i , i=1,2 which are less than half the length of the interval. We consider the case when 2π/5≤τ _i ≤π/2 and potentials q_k are functions from L_2 [τ _k,π ] , k=1,2 . We study the inverse spectral problem of recovering operators from their spectral characteristics. Four boundary value problems are considered and we prove that delays and potentials are uniquely determined from their spectra.