Bhatia, RajendraDrissi, Driss2012-11-122012-11-122005SIAM Journal of Matrix Anal. Application, v 27, no. 1, p 103-114http://hdl.handle.net/10263/4792enPositive definite matrixPositive definite functionFourier transformBochner's theoremLyapunov matrix equationOperator meanGeneralized Lyapunov equations and positive definite functionsArticle