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RE: PatternMatching with Dt[]

• To: mathgroup at smc.vnet.net
• Subject: [mg37291] RE: [mg37264] PatternMatching with Dt[]
• From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
• Date: Tue, 22 Oct 2002 04:47:11 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

>-----Original Message-----
>From: Johannes Ludsteck
To: mathgroup at smc.vnet.net
>[mailto:johannes.ludsteck at wiwi.uni-regensburg.de]
>Sent: Monday, October 21, 2002 8:29 AM
>To: mathgroup at smc.vnet.net
>Subject: [mg37291] [mg37264] PatternMatching with Dt[]
>
>
>I would like to replace Dt[x_] in a complex 
>expression. For example consider
>
>Dt[x]/.Dt[arg_]->f[arg]
>
>where x is a pure Symbol (has no value).
>However, Mathematica refuses apply the rule.
>Various other attempts, for example 
>Unevaluted[Dt[arg_]]:>f[arg]
>and HoldForm[...] were unsuccessful.
>
>I managed to  circumvent the problem by
>Dt[x]/.Dt->fun
>However, I were more happy if I understood why the 
>first attempt was not successful.
>Can someone explain?
>
>Best regards,
>	Johannes Ludsteck

Johannes,

Dt[x] /. HoldPattern[Dt[arg_]] -> f[arg]


....

Dt[arg_]

Dt[arg]*Derivative[1, 0][Pattern][arg, _]

....the total derivative of arg_ !

--
Hartmut