论文标题
状态依赖延迟图:投影的数值算法和动态
State dependent delay maps: numerical algorithms and dynamics of projections
论文作者
论文摘要
这项工作涉及一类延迟微分方程(DDE)的动态,我们称之为状态依赖延迟图。这些图是通过延迟微分方程生成的,其中当前状态的导数仅取决于延迟变量,而不取决于未删除的状态。但是,我们允许延迟本身是状态变量的函数。具有恒定延迟的延迟映射可以被明确重写为适当的功能空间上的离散时间动态系统,并且具有小状态依赖项的延迟映射可以看作是``非自治'扰动''。我们为这种扰动的库奇问题开发了一个固定点公式,并在适当的假设下获得了地图的正向迭代。 该证明具有建设性,并导致我们为说明性示例实施的数值过程,包括Cubic Ikeda和Mackey-Glass系统,具有恒定和国家依赖性延迟。在证明了该方法的局部收敛结果之后,我们使用数据分析工具来研究更多定性/全球收敛问题,以进行时间序列分析(维度和拓扑措施从持续的同源性得出)。使用这些工具,我们量化了有限尺寸投影中动力学的收敛性与无限尺寸系统的动力学。
This work concerns the dynamics of a certain class of delay differential equations (DDEs) which we refer to as state dependent delay maps. These maps are generated by delay differential equations where the derivative of the current state depends only on delayed variables, and not on the un-delayed state. However, we allow that the delay is itself a function of the state variable. A delay map with constant delays can be rewritten explicitly as a discrete time dynamical system on an appropriate function space, and a delay map with small state dependent terms can be viewed as a ``non-autonomous'' perturbation. We develop a fixed point formulation for the Cauchy problem of such perturbations, and under appropriate assumptions obtain the existence of forward iterates of the map. The proof is constructive and leads to numerical procedures which we implement for illustrative examples, including the cubic Ikeda and Mackey-Glass systems with constant and state-dependent delays. After proving a local convergence result for the method, we study more qualitative/global convergence issues using data analytic tools for time series analysis (dimension and topological measures derived from persistent homology). Using these tools we quantify the convergence of the dynamics in the finite dimensional projections to the dynamics of the infinite dimensional system.