symbolic and perturbative recursivity

*To*: mathgroup at smc.vnet.net*Subject*: [mg31711] symbolic and perturbative recursivity*From*: Roberto Campanha <campanha at rc.unesp.br>*Date*: Wed, 28 Nov 2001 01:29:34 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Dear Mathematica Group users, How I can do symbolic recursion on subscribed indexes? The problem is: A [x,y,t] = d1*A [x,y,t]+ d2*A [x,y,t] +tau*d3*A [x,y,t] i,j i-1,j i,j-1 i+1,j+1 knowing that A [x,y,t]=r0 0,0 and all terms with negative indexes are zero. This recursive scheme is also a perturbative expansion in tau, say we want terms up to tau^(k). I can not to change the index i+1=k because there is another envolved combinations of indexes, say i-2,j+1, and d1,d2 and d3 are derivative operators. Jose R. Campanha Department of Physics UNESP - Rio Claro - Sao Paulo - Brazil mail: campanha at rc.unesp.br