Traces for Sturm-Liouville operators with frozen argument on star graphs (Q2302223)

The regularized trace is calculated for the boundary value problem defined by the differential equation on a star-type graph with $d$ edges: \[ -y''_j(x)+q_j(x)y_j(a_j)=\lambda y_j(x),\quad x\in(0,\pi),\; j=\overline{1,d} \] with standard matching conditions in the interior vertex and boundary conditions in the boundary vertices.