Abstract
The problem of investigation of the spectral properties of the operators which are regularly solvable with respect to minimal operators T₀(Mp) and T₀(MP) generated by a general quasi-differential expression Mp and its formal adjoint $M_p^ + $ on any finite number of intervals Ip = (ap, bp), p = 1,... , N, are studied in the setting of the direct sums of Lwp(ap, bp)-spaces of functions defined on each of the separate intervals. These results extend those of formally symmetric expression M studied in [1] and [15] in the single-interval case, and also extend those proved in [10] and [13] in the general case.