Re: Re: Re: More /.{I->-1} craziness. Schools

*To*: mathgroup at smc.vnet.net*Subject*: [mg106920] Re: [mg106656] Re: [mg106882] Re: More /.{I->-1} craziness. Schools*From*: DrMajorBob <btreat1 at austin.rr.com>*Date*: Thu, 28 Jan 2010 02:44:37 -0500 (EST)*References*: <hjbvc0$2tp$1@smc.vnet.net> <hjeqh1$g3c$1@smc.vnet.net>*Reply-to*: drmajorbob at yahoo.com

0 and 1 are not "fuzzballs", so what interval could be >= 1 and also 0.? Bobby On Wed, 27 Jan 2010 00:44:22 -0600, Daniel Lichtblau <danl at wolfram.com> wrote: > Richard Fateman wrote: >> [...] >> If all of Mathematica functionality were available in the free player >> version, WRI would need to drastically change its business model. And >> even it it were free, we still have behavior like this: (..for some >> values of zero) >> >> {x >== 1, x > 0, x} evaluates to {True, False, 0.} >> >> RJF > > Let's take simple intervals, that is, intervals that are segments. > Define less and greater in the obvious ways, that is, one segment lies > strictly below the other (right endpoint of lesser is less than left > endpoint of larger). Let us further define two intervals to be equal > whenever they have nonempty intersection. > > With these definitions, which I think are sensible, the behavior you > describe above is consistent with arithmetic on intervals. As the > numbers involved, at least some of them, are fuzzballs, this strikes me > as an appropriate behavior. > > Daniel Lichtblau > Wolfram Research > -- DrMajorBob at yahoo.com