Existence Condition on Solutions to the Algebraic Riccati Equation
代数Riccati方程解的存在性条件

First,the existence conditions on the solutions to the algebraic Riccati equation are reviewed.Then,a strict proof is presented for a necessary and sufficient condition on the exis- tence of a unique optimal positive definite solution to this equa- tion.By using this condition,some untrue results on the design of robust decentralized controllers are corrected.