Re: Interval[{a,b}]-Interval[{a,b}] = 0?

*To*: mathgroup at smc.vnet.net*Subject*: [mg66634] Re: Interval[{a,b}]-Interval[{a,b}] = 0?*From*: Torsten Hennig <Torsten.Hennig at umsicht.fhg.de>*Date*: Thu, 25 May 2006 02:57:52 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

>Is this a bug or a feature? >Notice that Interval[{-1,1}]-Interval[{-1,1}] is Interval>[{-2,2}]. > >(I'm using Mathematica 5.1) > >RJF Hi Richard, The sum I + J is defined as I + J = {i+j : i in I, j in J} for sets I and J in IR. So I - I = 2*I is correct for I = [-1;1]. Best wishes Torsten.