Riccati Differential Equations

Presents the necessary auxiliary facts from algebra, functional analysis and Lie group analysis. This book illustrates theory with solutions of numerous examples. It also presents the matrix Riccati equations. It deals with theoretical questions concerning matrix and operator equations based on various applied problems from mathematical physics.

The scalar Riccati equation y' = p(t) Y to the second power + q(t) y+r(t) has the following well-known properties: (I) If one solution is known, the complete solution is obtainable by two quadratures; (II) If two solutions are known, the complete solution is obtainable by one quadrature; (III) The crossratio of any four distinct solutions is constant. The scalar Riccati equation has been generalized to systems. Adoption of one or the other of two particular viewpoints leads to the matrix equations u' = Au - u alpha u (u is n x 1) and Y' = KY + L - YMY - YN (Y is n x m). This paper shows that there is an expression for the complete solution of equations of the first type, and that an expression for the complete solution of equations of the second type can be obtained by quadratures from the complete solution of the first type. Following this, properties corresponding to (II) and (III) are established for the first equation. (Author).

Conceived by Count Jacopo Francesco Riccati more than a quarter of a millennium ago, the Riccati equation has been widely studied in the subsequent centuries. Since its introduction in control theory in the sixties, the matrix Riccati equation has known an impressive range of applications, such as optimal control, H? optimization and robust stabilization, stochastic realization, synthesis of linear passive networks, to name but a few. This book consists of 11 chapters surveying the main concepts and results related to the matrix Riccati equation, both in continuous and discrete time. Theory, applications and numerical algorithms are extensively presented in an expository way. As a foreword, the history and prehistory of the Riccati equation is concisely presented.