{ "id": "2108.11984", "version": "v1", "published": "2021-08-26T18:27:57.000Z", "updated": "2021-08-26T18:27:57.000Z", "title": "Characterization of a new class of stochastic processes including all known extensions of the class $(Σ)$", "authors": [ "Fulgence Eyi Obiang", "Paule Joyce Mbenangoye", "Octave Moutsinga" ], "comment": "17 Pages", "categories": [ "math.PR" ], "abstract": "This paper contributes to the study of class $(\\Sigma^{r})$ as well as the c\\`adl\\`ag semi-martingales of class $(\\Sigma)$, whose finite variational part is c\\`adl\\`ag instead of continuous. The two above-mentioned classes of stochastic processes are extensions of the family of c\\`adl\\`ag semi-martingales of class $(\\Sigma)$ considered by Nikeghbali \\cite{nik} and Cheridito et al. \\cite{pat}; i.e., they are processes of the class $(\\Sigma)$, whose finite variational part is continuous. The two main contributions of this paper are as follows. First, we present a new characterization result for the stochastic processes of class $(\\Sigma^{r})$. More precisely, we extend a known characterization result that Nikeghbali established for the non-negative sub-martingales of class $(\\Sigma)$, whose finite variational part is continuous (see Theorem 2.4 of \\cite{nik}). Second, we provide a framework for unifying the studies of classes $(\\Sigma)$ and $(\\Sigma^{r})$. More precisely, we define and study a new larger class that we call class $(\\Sigma^{g})$. In particular, we establish two characterization results for the stochastic processes of the said class. The first one characterizes all the elements of class $(\\Sigma^{g})$. Hence, we derive two corollaries based on this result, which provides new ways to characterize classes $(\\Sigma)$ and $(\\Sigma^{r})$. The second characterization result is, at the same time, an extension of the above mentioned characterization result for class $(\\Sigma^{r})$ and of a known characterization result of class $(\\Sigma)$ (see Theorem 2 of \\cite{fjo}). In addition, we explore and extend the general properties obtained for classes $(\\Sigma)$ and $(\\Sigma^{r})$ in \\cite{nik,pat,mult, Akdim}.", "revisions": [ { "version": "v1", "updated": "2021-08-26T18:27:57.000Z" } ], "analyses": { "keywords": [ "stochastic processes", "finite variational part", "second characterization result", "mentioned characterization result", "nikeghbali" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable" } } }