Extracting free parameters from a Solve result

*To*: mathgroup at smc.vnet.net*Subject*: [mg93914] Extracting free parameters from a Solve result*From*: carlos at colorado.edu*Date*: Fri, 28 Nov 2008 05:09:48 -0500 (EST)

In solving a Sylvester matrix equation, Solve is given 18 equations in 10 variables: v= {W11,W12,W13,W14,W22, W23,W24,W33,W34,W44} It returns {{W11->W44, W12->-W34, W13->W34, W14->-W23-W33+W44, W22->W33, W24->-W34}} How do I extract the 4 variables: W44,W34,W23,W33 left over on the right of the ->, and place them in an ordered list: pars={W23,W33,W34,W44} I guess the simplest way would be to Drop the dependent variables from the v list but the details escape me. Thanks.