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arXiv 2303.14743math.PRmath.CA
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变阶分数阶松弛方程的更新过程

Renewal processes linked to fractional relaxation equations with variable order

Luisa Beghin, Lorenzo Cristofaro, Roberto Garrappa

摘要:

本文引入并研究了由导数阶数随时间变化的时间分数阶松弛方程定义的更新过程$α(t)$.特别是,我们使用了Scarpi在70年代引入的算子,后来在Garrappa et al.(2021)的正则化Caputo意义上重新表述,在所谓的一般分数微积分的框架内。所得到的模型扩展了著名的时间分数泊松过程的固定顺序$α\in (0,1)$,并试图克服其局限性,包括在常数的导数阶(因此的记忆程度的到达间隔)相对于时间。证明了变阶更新过程不属于通常的从属表示,因为它不能简单地定义为随机时间的泊松过程(如标准分式情形).最后分析了一个相关的连续时间随机游动模型,建立了它的极限行为。

英文摘要:

We introduce and study here a renewal process defined by means of a time-fractional relaxation equation with derivative order $α(t)$ varying with time $t\geq0$. In particular, we use the operator introduced by Scarpi in the Seventies and later reformulated in the regularized Caputo sense in Garrappa et al. (2021), inside the framework of the so-called general fractional calculus. The model obtained extends the well-known time-fractional Poisson process of fixed order $α\in (0,1)$ and tries to overcome its limitation consisting in the constancy of the derivative order (and therefore of the memory degree of the interarrival times) with respect to time. The variable order renewal process is proved to fall outside the usual subordinated representation, since it can not be simply defined as a Poisson process with random time (as happens in the standard fractional case). Finally a related continuous-time random walk model is analysed and its limiting behavior established.

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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