2020/06/01 by Алессандро Порталури, Portaluri, Alessandro, Li Wu +1
Mathematics · Physics and Astronomy · #47H11 #55M25 #58J20 #58J30 #Advanced Algebra and Geometry #Classical Analysis and ODEs (math.CA) #Dynamical Systems (math.DS) #FOS: Mathematics #Functional Analysis (math.FA) #Geometric and Algebraic Topology #Quantum chaos and dynamical systems
paper · pdf · doi:10.48550/arxiv.2006.00956
openalex publication_date 2020/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In 2005 a new topological invariant defined in terms of the Brouwer degree of a determinant map, was introduced by Musso, Pejsachowicz and the first name author for counting the conjugate points along a semi-Riemannian geodesic. This invariant was defined in terms of a suspension of a complexified family of linear second order Dirichlet boundary value problems. In this paper, starting from this result, we generalize this invariant to a general self-adjoint Morse-Sturm system and we prove a new spectral flow formula. Finally we discuss the relation between this spectral flow formula and the Hill's determinant formula and we apply this invariant for detecting instability of periodic orbits of a Hamiltonian system.