A type of nonlinear equation that arises in the context of infinite-horizon optimal control problems in continuous or discrete time.


Continuous time algebraic Riccatti equation

Where is an unknown Positive-Definite Matrix

Positive-Definite Matrix

A symmetric matrix with all positive eigenvalues. NOTE: All symmetric matrices have only real eigenvalues

For a matrix, , to be positive-semidefinite the following has to hold

Criterion

Given that is a symmetric real matrix


Can be written generally as

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