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arXiv 1402.6596math.PR
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具有$\mathbb{L}^2$的二次倒向随机微分方程--终端数据的存在性结果、Krylov估计和Ito-Krylov公式

Quadratic BSDEs with $\mathbb{L}^2$--terminal data Existence results, Krylov's estimate and Itô--Krylov's formula

Khaled Bahlali, M'hamed Eddahbi, Youssef Ouknine

摘要:

第一步,我们建立了一个大类的二次向后随机微分方程(QBSDES)的连续生成元和一个仅仅平方可积〔的〕终端条件的解的存在性(有时是唯一性)。我们的方法是从文献中存在的不同。虽然我们关注的是QBSDES,我们的存在性结果也涵盖了线性增长的BSDES,保持$ξ$平方可积〔的〕在这两种情况下。作为副产品,建立了一类二次偏微分方程(QPDE)具有平方可积〔的〕的粘性解的存在性。在第二步中,我们考虑QBSDES与可测生成器,我们建立了一个Krylov型先验估计的解决方案。然后,我们推导出伊藤-克雷洛夫的变量变换公式。这使我们能够建立各种存在性和唯一性的结果类QBSDE与平方可积〔的〕终端条件,有时只是一个可测的发电机。我们的研究结果表明,特别是,既不存在指数时刻的终端数据,也不连续的发电机的存在性和/或唯一性的二次倒向随机微分方程的解决方案是必要的。对一类QBSDE的解也建立了比较定理。

英文摘要:

In a first step, we establish the existence (and sometimes the uniqueness) of solutions for a large class of quadratic backward stochastic differential equations (QBSDEs) with continuous generator and a merely square integrable terminal condition. Our approach is different from those existing in the literature. Although we are focused on QBSDEs, our existence result also covers the BSDEs with linear growth, keeping $ξ$ square integrable in both cases. As byproduct, the existence of viscosity solutions is established for a class of quadratic partial differential equations (QPDEs) with a square integrable terminal datum. In a second step, we consider QBSDEs with measurable generator for which we establish a Krylov's type a priori estimate for the solutions. We then deduce an Itô--Krylov's change of variable formula. This allows us to establish various existence and uniqueness results for classes of QBSDEs with square integrable terminal condition and sometimes a merely measurable generator. Our results show, in particular, that neither the existence of exponential moments of the terminal datum nor the continuity of the generator are necessary to the existence and/or uniqueness of solutions for quadratic BSDEs. Some comparison theorems are also established for solutions of a class of QBSDEs.

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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