Filomat, vol.36, no.7, pp.2411-2426, 2022 (SCI-Expanded)
© 2022, University of Nis. All rights reserved.In this work, we find the asymptotic formulas for the sum of the negative eigenvalues smaller than −ε (ε > 0) of a self-adjoint operator L defined by the following differential expression ℓ(y) = −(p(x)y′ (x))′ − Q(x)y(x) with the boundary condition y(0) = 0 in the space L2 (0, ∞; H).