ordering a group of symbolic operators

*To*: mathgroup at smc.vnet.net*Subject*: [mg128316] ordering a group of symbolic operators*From*: Yaj <ybhattacharya at gmail.com>*Date*: Sat, 6 Oct 2012 01:51:52 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Appreciate any help with the following (newbie to Mathemtica) I have a following expression, consisting of groups/strings of symbolic operators phi_c.delta_a.phi_b.delta_c + delta_c.phi_c.delta_f.phi_c + ... Need to rearrange the above such that all the phi-s are on the left and all the deltas are on the right, i.e. REWRITE the above as phi_c.phi_b.delta_a.delta_c + phi_c.phi_c.delta_c.delta_f + .... The order of the (phi)s i.e. whether phi_c is to the left of phi_b doesn't matter, but all the (phi)s must be towards the left of all (delta)s in each string. Please note that the (dots) are not necessarily multiplication.