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

*To*: mathgroup at smc.vnet.net*Subject*: [mg66629] Re: Interval[{a,b}]-Interval[{a,b}] = 0?*From*: Johan Grönqvist <johan.gronqvist at gmail.com>*Date*: Wed, 24 May 2006 04:10:16 -0400 (EDT)*Organization*: Lund University, Sweden*References*: <e510r2$8eg$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Richard Fateman wrote: > Is this a bug or a feature? > Notice that Interval[{-1,1}]-Interval[{-1,1}] is Interval[{-2,2}]. Interval arithmetic with a hopefully understandable notation: You start with [-1,1] and subtract from that [-1,1] This means: Result = { x-y | x and y are in [-1,1] } Then the Result will be A = [-2,2], and this is what you get. Try also [-1,1] * [-1,1] to see that you get a result obtained in the same way. This is good for calculating with numbers having errors, among (probably) other things. say [x-error,x+error] - [y-error,y+error] and you get the result x-y with the error in the form [x-y - 2error, x-y + 2error] Good for handling experimental data. / johan > > (I'm using Mathematica 5.1) > > RJF >