RE: How to do symbolic matrix manipulations

*To*: mathgroup at smc.vnet.net*Subject*: [mg92289] RE: [mg92276] How to do symbolic matrix manipulations*From*: "Jose Luis Gomez" <jose.luis.gomez at itesm.mx>*Date*: Sat, 27 Sep 2008 06:46:56 -0400 (EDT)*References*: <200809261023.GAA09890@smc.vnet.net>

In Mathematica the asterisk is used for commutative multiplication, for the noncommutative matrix multiplication you must use a dot: a.b See this link: http://reference.wolfram.com/mathematica/ref/Dot.html Be sure to check also MatrixPower, or you will also have problems with powers of matrices: http://reference.wolfram.com/mathematica/ref/MatrixPower.html Hope that helps Jose Mexico -----Mensaje original----- De: Peng Yu [mailto:pengyu.ut at gmail.com] Enviado el: Viernes, 26 de Septiembre de 2008 05:24 Para: mathgroup at smc.vnet.net Asunto: [mg92276] How to do symbolic matrix manipulations Hi, Suppose I have matrices a and b, which does not have any value yet. If I write b * a, mathematica would give me "a b". I'm wondering how to make it know that a and b are matrices, so that it would give me "b a" rather than "a b". Thanks, Peng

**References**:**How to do symbolic matrix manipulations***From:*"Peng Yu" <pengyu.ut@gmail.com>