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A mysterious reference

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16533] A mysterious reference
  • From: Jack Goldberg <jackgold at math.lsa.umich.edu>
  • Date: Tue, 16 Mar 1999 04:00:10 -0500
  • Sender: owner-wri-mathgroup at wolfram.com

To the Mavens of Mathematica,

The last sentence in the first paragraph on page 265
of "The Mathematica Book" reads:  "You must load an appropriate 
Mathematica package to make this possible".  Steven Wolfram is 
refering here to a problem that arises (in one form or another) 
rather frequently in the posts to this newsgroup, namely, if you 
set  n  to be in integer by this device:

	n /: IntegerQ[n] = True

then Mathematica does not draw any conclusions from this fact.  In particular,
it does not know that  n^2  is also an integer!  

So my question:  To what package is Wolfram refering in the sentence
I quoted above?  

Here is what I have found out after 15 minutes of tinkering.  On my 
personal version of MathSource I discovered a package called  Declare.m
which may be this mystery reference.  However, on the version of
MathSource available from the Web site, there is no such package.  

Does anyone know what's going on?  (I have been experimenting with 
my own attempt to write such a package but I have no interest in 
re-inventing the wheel.  If anyone has done this already, I'd be
delighted to here from you.  Perhaps others in this group would 
be interested as well).

Jack 





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