Traces for Sturm–Liouville Operators on a Caterpillar Graph

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 analysis. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.