Template-Type: ReDIF-Paper 1.0 Series: Tinbergen Institute Discussion Papers Creation-Date: 2001-04-11 Number: 01-043/2 Author-Name: Ronald J. Balvers Author-Email: rbalvers@wvu.edu Author-Workplace-Name: West Virginia University, USA Author-Name: Douglas W. Mitchell Author-Workplace-Name: West Virginia University, USA Title: Reducing the Dimensionality of Linear Quadratic Control Problems Abstract: In linear-quadratic control (LQC) problems with singular control cost matrix and/or singular transition matrix, we derive a reduction of the dimension of the Riccati matrix, simplifying iteration and solution. Employing a novel transformation, we show that, under a certain rank condition, the matrix of optimal feedback coefficients is linear in the reduced Riccati matrix. For a substantive class of problems, our technique permits scalar iteration, leading to simple analytical solution. By duality the technique can also be applied to Kalman filtering problems with a singular measurement error covariance matrix. Classification-JEL: C61; C63; D83 Keywords: Linear-quadratic control; Riccati equation; Riccati reduction; Kalman filtering; Intertemporal optimization File-Url: https://papers.tinbergen.nl/01043.pdf File-Format: application/pdf File-Size: 242999 bytes Handle: RePEc:tin:wpaper:20010043