Feng Wang

• Nanjing University of Science and Technology

In this work, we consider Dirac-type operators with a constant delay of less than half of the interval and not less than two-fifths of the interval. For our considered Dirac-type operators, two inverse spectral problems are studied. Specifically, reconstruction of two complex L2-potentials is studied from complete spectra of two boundary value prob...

In this work, we consider the spectral problems for the Sturm–Liouville operators on a caterpillar graph with the standard matching conditions in the internal vertices and the Neumann or the Dirichlet conditions in the boundary vertices. The regularized trace formulae of these operators are established by using the residue techniques of complex ana...

We introduce Dirac-type operators with a global constant delay on a star graph consisting of m equal edges. For our introduced operators, we formulate an inverse spectral problem that is recovering the potentials from the spectra of two boundary value problems on the graph with a common set of boundary conditions at all boundary vertices except for...

We introduce Dirac-type operators with a global constant delay on a star graph consisting of $m$ equal edges. For our introduced operators, we formulate an inverse spectral problem that is recovering the potentials from the spectra of two boundary value problems on the graph with a common set of boundary conditions at all boundary vertices except f...

We consider the Sturm-Liouville operator on the lasso graph with a segment and a loop joined at one point, which has arbitrary length. The Ambarzumyan's theorem for the operator is proved, which says that if the eigenvalues of the operator coincide with those of the zero potential, then the potential is zero.

We consider the vector-impulsive Sturm-Liouville problem with Neumann conditions. The Ambarzumyan$^{\textbf{,}}$s theorem for the problem is proved, which states that if the eigenvalues of the problem coincide with those of the zero potential, then the potential is zero.

In this work, we consider Dirac-type operators with a constant delay less than two-fifths of the interval and not less than one-third of the interval. For our considered Dirac-type operators, an incomplete inverse spectral problem is studied. Specifically, when two complex potentials are known a priori on a certain subinterval, reconstruction of th...

In this work, we consider Dirac-type operators with a constant delay less than half of the interval and not less than two fifths of the interval. For our considered Dirac-type operators, an inverse spectral problem is studied. Specifically, reconstruction of two complex $L_{2}$-potentials is studied from complete spectra of two boundary value probl...

In this work we consider boundary value problems for the Sturm–Liouville operator with constant delays on a star graph. We assume that the potentials and the delay constants are known a priori on all the edges except one, and study the partial inverse problem, which consists in recovering the potential and the the delay constant on remaining edge f...

In this work we consider the spectral problems for Sturm–Liouville operators with constant delays on a star graph. First the asymptotics for the large eigenvalues of these operators are derived. Secondly the regularized trace formulae of these operators are established with the method of complex analysis.

We consider the inverse eigenvalue problems for stationary Dirac systems with differentiable self-adjoint matrix potential. The theorem of Ambarzumyan for a Sturm-Liouville problem is extended to Dirac operators, which are subject to separation boundary conditions or periodic (semi-periodic) boundary conditions, and some analogs of Ambarzumyan’s th...