Re: Re: Bug Report - Two numerical values for a same variable

*To*: mathgroup at smc.vnet.net*Subject*: [mg54300] Re: [mg54271] Re: Bug Report - Two numerical values for a same variable*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Wed, 16 Feb 2005 14:36:27 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <00ed01c512b0$2f242850$6400a8c0@Main> <curpbn$r28$1@smc.vnet.net> <200502150438.XAA29728@smc.vnet.net>*Reply-to*: murray at math.umass.edu*Sender*: owner-wri-mathgroup at wolfram.com

The manipulations below are precisely what's so confusing about Rational objects (and Complex objects) being atoms. If 1/2 /. Rational[x_, 2] -> Rational[x, 7] works, then why not the following? Part[Rational[1, 2], 2] I can "believe" that integers and reals (and maybe strings) are atoms; but believing that rationals and complex numbers are atoms is a hard thing to swallow! This has always bothered me -- and hence given me trouble trying to, um, rationalize this to students when I've taught Mathematica. Scott Hemphill wrote: > DrBob <drbob at bigfoot.com> writes: > > >>That explains it, but only in the sense that "things fall down" is a theory of gravity. Why should Rationals be atomic, for goodness sake? And how did I use Mathematica all this time without hearing about it? >> >>Sigh... > > > > In[1]:= FullForm[1/2] > > Out[1]//FullForm= Rational[1, 2] > > In[2]:= 1/2 /. Rational[x_,2] -> Rational[x,7] > > 1 > Out[2]= - > 7 > > Scott -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**Follow-Ups**:**Re: Re: Re: Bug Report - Two numerical values for a same variable***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**Re: Re: Re: Bug Report - Two numerical values for a same variable***From:*Sseziwa Mukasa <mukasa@jeol.com>

**References**:**Re: Bug Report - Two numerical values for a same variable***From:*Scott Hemphill <hemphill@hemphills.net>