On one-dimensional stochastic differential equations involving the maximum process

TL;DR

This paper establishes existence and uniqueness results for various one-dimensional stochastic differential equations involving the maximum process, local time, and non-Lipschitz coefficients, expanding the understanding of such SDEs.

Contribution

It introduces new existence and uniqueness results for SDEs with maximum process perturbations, including non-Lipschitz coefficients and additional terms like local time.

Findings

Proved existence and pathwise uniqueness for four types of SDEs involving maximum process.

Extended results to non-Lipschitz coefficients in the first three SDE types.

Established strong solutions and uniqueness under Lipschitz conditions for a combined SDE with maximum and minimum processes.

Abstract

We prove existence and pathwise uniqueness results for four different types of stochastic differential equations (SDEs) perturbed by the past maximum process and/or the local time at zero. Along the first three studies, the coefficients are no longer Lipschitz. The first type is the equation \label{eq1} X_{t}=\int_{0}^{t}\sigma (s,X_{s})dW_{s}+\int_{0}^{t}b(s,X_{s})ds+\alpha \max_{0\leq s\leq t}X_{s}. The second type is the equation \label{eq2} {l} X_{t} =\ig{0}{t}\sigma (s,X_{s})dW_{s}+\ig{0}{t}b(s,X_{s})ds+\alpha \max_{0\leq s\leq t}X_{s}\,\,+L_{t}^{0}, X_{t} \geq 0, \forall t\geq 0. The third type is the equation \label{eq3} X_{t}=x+W_{t}+\int_{0}^{t}b(X_{s},\max_{0\leq u\leq s}X_{u})ds. We end the paper by establishing the existence of strong solution and pathwise uniqueness, under Lipschitz condition, for the SDE \label{e2} X_t=\xi+\int_0^t \si(s,X_s)dW_s +\int_0^t b(s,X_s)ds +\al\max_{0\leq s\leq t}X_s +\be \min_{0\leq s \leq t}X_s.