{ "id": "2009.13189", "version": "v1", "published": "2020-09-28T10:03:30.000Z", "updated": "2020-09-28T10:03:30.000Z", "title": "SPHARMA approximations for stationary functional time series on the sphere", "authors": [ "Alessia Caponera" ], "categories": [ "math.ST", "math.PR", "stat.TH" ], "abstract": "In this paper, we focus on isotropic and stationary sphere-cross-time random fields. We first introduce the class of spherical functional autoregressive-moving average processes (SPHARMA), which extend in a natural way the spherical functional autoregressions (SPHAR) recently studied in [8, 7]; more importantly, we then show that SPHAR and SPHARMA processes of sufficiently large order can be exploited to approximate every isotropic and stationary sphere-cross-time random field, thus generalizing to this infinite-dimensional framework some classical results on real-valued stationary processes. Further characterizations in terms of functional spectral representation theorems and Wold-like decompositions are also established.", "revisions": [ { "version": "v1", "updated": "2020-09-28T10:03:30.000Z" } ], "analyses": { "subjects": [ "62M15", "62M10", "60G15", "60F05", "62M40", "60G60" ], "keywords": [ "stationary functional time series", "spharma approximations", "stationary sphere-cross-time random field", "functional autoregressive-moving average processes", "functional spectral representation theorems" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }