RO  EN
IMCS/Publications/BASM/Issues/BASM n.1 (7), 1992/

On the spectrum of perturbed differential operators with periodic coefficients. (Russian)

Authors: Kozhukhari P. A.

Abstract

Some conditions are established, which quarante the absence of eigenvalues for the differential operator
$$
H=\sum^n_{k=0}h_k(t)\left(\frac d{dt}\right)^{n-k},
$$
where $h_k(t)=a_k(t)+b_k(t)$; $a_k(t)$ ($k=0,1,\dots, n; \ a_0(t)\ne 0$) -- are functions of period $T$;
$b_k(t)$ ($k=0,1,\dots, n; \ b_0(t)\ne 0$) -- are measurable functions (in general complex). Operator is acting in Banach space $L_p(0,\infty)$ ($1\le p<\infty$) \ (the choice of boundary conditions is not important). The obtained results are true for differential operator with matrix coefficients.