finding independent variable groups

*To*: mathgroup at smc.vnet.net*Subject*: [mg32406] finding independent variable groups*From*: romoscanu at imes.mavt.ethz.ch (Ioan Alexandre Romoscanu)*Date*: Sat, 19 Jan 2002 01:16:43 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I wonder if it is possible to do the following formula manipulation task with Mathematica. Suppose you have a function of 3 variables [x,y,z], where only the ratio x/y occurs. Example f[x_,y_,z_]=(x/y) Exp[z] If now you have a large formula of more than 3 variables, where however certain variables always occur grouped together, in the same pattern (like x and y above). Is there a way to make Mathematica find out such groups of variables in a larger expression? Thank you for any help A.I.R.