A Stochastic Reconstruction Theorem on Rectangular Increments with an Application to a Mixed Hyperbolic SPDE
Carlo Bellingeri, Hannes Kern
TL;DR
This work extends the stochastic reconstruction theorem to random germs with rectangular increments adapted to multiparameter filtrations, enabling a robust framework for analyzing mixed stochastic systems in multiple dimensions. The authors develop a wavelet-based reconstruction with a coherent rectangular-increment structure, prove existence and uniqueness of the reconstructed random distributions, and apply the theory to a novel hyperbolic SPDE that combines Walsh integration with Young products. They establish a full fixed-point theory in the Young regime, including composition, multiplication, and integration of germs, yielding local and global well-posedness results. Additionally, the paper clarifies the connection between reconstruction and stochastic sewing in higher dimensions, showing how sewing emerges as a special case and highlighting the broader applicability to products of deterministic and stochastic objects that arise in hyperbolic SPDEs and stochastic analysis.
Abstract
We extend the stochastic reconstruction theorem to a setting where the underlying family of distributions satisfies some natural conditions involving rectangular increments. This allows us to prove the well-posedness of a new class of mixed stochastic partial differential of hyperbolic type which combines standard Walsh stochastic integration and Young products.
