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arXiv · 2506.23947

Explicit modified Euler approximations of the Aït-Sahalia type model with Poisson jumps

Yingsong Jiang·Ruishu Liu·Minhong Xu
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Abstract

This paper focuses on mean-square approximations of a generalized Aït-Sahalia interest rate model with Poisson jumps. The main challenge in the construction and analysis of time-discrete numerical schemes is caused by a drift that blows up at the origin, highly nonlinear drift and diffusion coefficients and positivity-preserving requirement. Due to the presence of the Poisson jumps, additional difficulties arise in recovering the exact order $1/2$ of convergence for the time-stepping schemes. By incorporating implicitness in the term $α_{-1}x^{-1} $ and introducing the modifications functions $f_h$ and $g_h$ in the recursion, a novel explicit Euler-type scheme is proposed, which is easy to implement and preserves the positivity of the original model unconditionally, i.e., for any time step-size $h>0$. A mean-square convergence rate of order $1/2$ is established for the proposed scheme in both the non-critical and general critical cases. Finally, numerical experiments are provided to confirm the theoretical findings.

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Yingsong Jiang, Ruishu Liu, Minhong Xu. 2025-06-30. Explicit modified Euler approximations of the Aït-Sahalia type model with Poisson jumps. https://arxiv.org/abs/2506.23947

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