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Re: Defining operators containing derivatives

  • To: mathgroup at smc.vnet.net
  • Subject: [mg67892] Re: Defining operators containing derivatives
  • From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
  • Date: Wed, 12 Jul 2006 05:05:18 -0400 (EDT)
  • Organization: Uni Leipzig
  • References: <e8vtu8$su5$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

A[x_, theta_][f_] := D[f, x] + Sinh[2*x]*D[f, 
theta]
B[x_, theta_][f_] := -Sinh[x + I*theta]*D[f, x] + 
Cosh[2*x]*D[f, theta] +
Tanh[5*x]*f

and

B[x, theta]@ A[x, theta]@ f[x, theta] - A[x, 
theta]@ B[x, theta]@ f[x, theta]

Regards

  Jens

"cosmicstring" <cosmicstring at gmail.com> schrieb im 
Newsbeitrag news:e8vtu8$su5$1 at smc.vnet.net...
|I have been using Mathematica as a simple 
calculator but now I need
| something different which Mathematica is capable 
of but out of my
| knowledge.
|
| I have, say, two operators:
|
| A:=D[f[x,theta],x]+Sinh[2*x]*D[f[x,theta],theta]
| 
B:=-Sinh[x+I*theta*]*D[f[x,theta],x]+Cosh[2*x]*D[f[x,theta],theta]+Tanh[5*x]*f[x,theta]
|
| I want to define A and B as operators and apply 
them to any f[x,theta]
| as,
|
| AB f[x,theta]+BA g[x,theta]
|
| Any help would be appreciated.
| 



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