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arXiv 1909.03020math.PR
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纯跳半鞅

Pure-jump semimartingales

Aleš Černý, Johannes Ruf

摘要:

引入了一种新的关于整值随机测度的积分。与半鞅理论中普遍存在的有限变分积分(Jacod and Shiryaev,2003,II.1.5)不同,新积分在随机积分、复合和光滑变换下是封闭的。新的积分产生了一类以前未研究的纯跳跃过程:σ-局部有限变差纯跳跃过程。作为一个应用,证明了每个半鞅$X$都有唯一的分解$$X = X_0 + X^{\mathrm{qc}}+X^{\mathrm{dp}},$$,其中$X^{\mathrm{qc}}$是拟左连续的,$X^{\mathrm{dp}}$是一个σ-局部有限变差纯跳过程,它只在可料时跳,且都从零开始.该分解反映了局部鞅的经典结果(Yoeurp,1976,Theorme ~1.4),并给出了半鞅的连续时间分量和离散时间分量的严格意义.在此背景下,本文研究了一类更广泛的过程,等于他们的跳跃的总和在半鞅拓扑结构,并构建了一个分类层次的纯跳半鞅。

英文摘要:

A new integral with respect to an integer-valued random measure is introduced. In contrast to the finite variation integral ubiquitous in semimartingale theory (Jacod and Shiryaev, 2003, II.1.5), the new integral is closed under stochastic integration, composition, and smooth transformations. The new integral gives rise to a previously unstudied class of pure-jump processes: the sigma-locally finite variation pure-jump processes. As an application, it is shown that every semimartingale $X$ has a unique decomposition $$X = X_0 + X^{\mathrm{qc}}+X^{\mathrm{dp}},$$ where $X^{\mathrm{qc}}$ is quasi-left-continuous and $X^{\mathrm{dp}}$ is a sigma-locally finite variation pure-jump process that jumps only at predictable times, both starting at zero. The decomposition mirrors the classical result for local martingales (Yoeurp, 1976, Theoreme~1.4) and gives a rigorous meaning to the notions of continuous-time and discrete-time components of a semimartingale. Against this backdrop, the paper investigates a wider class of processes that are equal to the sum of their jumps in the semimartingale topology and constructs a taxonomic hierarchy of pure-jump semimartingales.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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