PatternMatching with Dt[]

*To*: mathgroup at smc.vnet.net*Subject*: [mg37264] PatternMatching with Dt[]*From*: "Johannes Ludsteck" <johannes.ludsteck at wiwi.uni-regensburg.de>*Date*: Mon, 21 Oct 2002 02:29:28 -0400 (EDT)*Organization*: Universitaet Regensburg*Sender*: owner-wri-mathgroup at wolfram.com

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 Ludsteck Economics Department University of Regensburg Universitaetsstrasse 31 93053 Regensburg Phone +49/0941/943-2741