On norm bounds for algebraic Riccati and Lyapunov equations
Rajni V. Patel, M. Toda · IEEE Transactions on Automatic Control · 1978
New lower bounds on the spectral norms of the positive definite solutions to the continuos and discrete algebraic matrix Riccati and Lyapunov equations are derived. These bounds are much easier to compute than previously available bounds and appear to be considerably tighter in many cases.