Decomposition of discontinuous flows of diffeomorphisms: jumpings, geometrical and topological aspects (2501.01750v1)

Abstract: Let $M$ be a compact manifold equipped with a pair of complementary foliations, say horizontal $\mathcal{H}$ and vertical $\mathcal{V}$. In Melo, Morgado and Ruffino (Disc Cont Dyn Syst B, 2016, 21(9)) it is proved that if a semimartingale $X_t$ has a finite number of jumps in compact intervals then, up to a stopping time $\tau$, a stochastic flow of local diffeomorphisms in $M$ driven by $X_t$ can be decomposed into a process in the Lie group of diffeomorphisms which fix the leaves of $\mathcal{H}$ composed with a process in the Lie group of diffeomorphisms which fix the leaves of $\mathcal{V}$. Dynamics at the discontinuities of $X_t$ here are interpreted in the Marcus sense as in Kurtz, Pardoux and Protter \cite{KPP}. Here we enlarge the scope of this geometric decomposition and consider flows driven by arbitrary semimartingales with jumps and show explicit equations for each component. Our technique is based in an extension of the It^o-Ventzel-Kunita formula for stochastic flows with jumps. Geometrical and others topological obstructions for the decomposition are also considered: e.g. an index of attainability is introduced to measure the complexity of the dynamics with respect to the pair of foliations.