*To*: mathgroup@smc.vnet.net*Subject*: [mg11092] how to pull real numbers out of a linear funktion ?*From*: Roland Bollmann <roland@arnold.fkp.physik.th-darmstadt.de>*Date*: Sun, 22 Feb 1998 14:55:17 -0500

I want to define a function f[x_] with the property, that f[c_ x_] := c f[x] whenever c is a real number and f[c_ x_] := -c f[x] whenever c is a komplex number. It semms to me, that mathematica can not give a variable the attribute "real number" or "complex number". But it should be easy ... somehow ;-) Roland Bollmann (student of physics)