1-D Schrödinger operators with distributional potentials.
Main publications:
V. Mikhailets, V. Molyboga, “One-dimensional Schrödinger operators with singular periodic potentials”, The one-dimensional Schrödinger operators
$S(q)u:=-u''+q(x)u$, $u\in\mathrm{Dom}(S(q))$ with 1-periodic real-valued singular potentials $q(x)\in H_{per}^{-1}(\mathbb{R},\mathbb{R})$ are studied on the Hilbert space $L_2(\mathbb{R})$. An equivalence of five basic definitions for the operators $S(q)$ and their self-adjointness are established. A new proof of spectral continuity of the operators $S(q)$ is found. Endpoints of spectral
gaps are precisely described, Methods Funct. Anal. Topology, 14:2 (2008), 184–200
V. Mikhailets, V. Molyboga, “Singularly perturbed periodic and semiperiodic differential operators”, Ukrainian Math. J., 59:6 (2007), 785–797
V. A. Mikhailets, V. M. Molyboga, “On the Spectrum of Singular Perturbations of Operators on the Circle”, Mat. Zametki, 91:4 (2012), 629–632; Math. Notes, 91:4 (2012), 588–591