Positive dynamical or control systems have all their variables nonnegative. Euler discretization transforms a continuous-time system into a system on a discrete time scale. Some structural properties of the system may be preserved by discretization, while other may be lost. Four fundamental properties of positive systems are studied in the context of discretization: positivity, positive stability, positive reachability and positive observability. Both linear and nonlinear systems are investigated.

中文翻译：

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正系统离散化下的不变性

正动力或控制系统的所有变量均为非负。欧拉离散化将连续时间系统转换为离散时间范围内的系统。系统的某些结构属性可能会通过离散化保留，而其他一些属性可能会丢失。在离散化的背景下研究了正系统的四个基本属性：正性，正稳定性，正可达性和正可观性。研究了线性和非线性系统。