The null subset corresponds to the term 1. 空集则对应于常数项1。
We also prove that the system considered is exact null controllability at any time T> 0 when the input control acts on a non-empty open set, which is based on the finite time extinction and localization of the solution for the equation with a strong absorption term. Ω,则基于具有强吸收项的方程的解在有限时间熄灭及局部化性质,可以研究系统在任意时间T>0的精确零能控性。