No abstract

Abstract. The one-dimensional Dirac operator with periodic po-periodic, antiperiodic or a general strictly regular boundary condition (bc) has discrete spectrums. It is known that, for large enough |n| in the disc centered at n of radius 1/4, the operator has exactly two (periodic if n is even or antiperiodic if n is odd) eigenvalues λ + n and λ − n (counted according to multiplicity) and one eigenvalue µ bc n corresponding to the boundary condition (bc). We prove that the smoothness of the potential could be characterized by the decay rate of the sequence |δ