Re: Sum expansion

*To*: mathgroup at smc.vnet.net*Subject*: [mg32646] Re: [mg32630] Sum expansion*From*: BobHanlon at aol.com*Date*: Fri, 1 Feb 2002 16:10:44 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

In a message dated 2/1/02 2:26:08 AM, fischerc at itam.cas.cz writes: >I would like to arrange exression >A Sum [ B_i ,{i,1,s}] >into expression >Sum [ A B_i, {i,1,s} ] > >Following transformation code gives unwanted answer: >A*Sum[Subscript[B, i], {i, 1, s}] /. > a_*Sum[b_, {i, 1, s}] -> Sum[a*b, {i, 1, s}] >Result is >A s Bi > >I understand, why it behawes this way, but I dont know the correct way. > Use RuleDelayed A*Sum[Subscript[B,i], {i,1,s}] /. a_*Sum[b_, {i_, i0_, in_}] :> Sum[a*b, {i,i0,in}] Bob Hanlon Chantilly, VA USA