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Re: More questions on expanding function names

  • To: mathgroup at
  • Subject: [mg8263] Re: More questions on expanding function names
  • From: Paul Abbott <paul at>
  • Date: Sat, 23 Aug 1997 01:59:01 -0400
  • Organization: University of Western Australia
  • Sender: owner-wri-mathgroup at

Paulo Mouat wrote:

> Suppose I want to write a report that uses many of the advanced
> mathematical functions supported by Mathematica.  It makes sense to
> obtain an explicit mathematical form even if only to indicate that from
> then on Erf[x] would be a shorthand to 2/Sqrt[Pi] Integrate ...

The easy way of finding a definition for Erf[x] is to select the "Erf"
with the mouse and do "Find in Help..." under the Help menu. 

Note that I write "a" definition rather than "the" definition because
Mathematica is not actually using the integral definition when computing
symbolic or numeric values.  Instead it could be using a more general
hypergeomteric definition (or minimax approximation for numerical

> Also, I was interested in such representations so as to obtain explicit
> mathematical forms in intermediate or final results, avoiding the use
> of function names.  Since simple mathematics can lead to more
> complicated mathematics upon certain calculations, I would like to avoid
> the introduction of advanced function names so that the output is
> readable by someone not familiar with the particular Mathematica
> representation of advanced functions.

I don't think this will help.  In fact I think it is a bad idea. 
Leaving all the integrals there will just complicate the output -- which
is one reason why special functions like erf(x) were introduced in the
first place!  If any function arises that you have not heard of -- say
the Meijer G function -- simply select the function and look it up in


Paul Abbott                                   Phone: +61-8-9380-2734
Department of Physics                           Fax: +61-8-9380-1014
The University of Western Australia           
Nedlands WA  6907                     mailto:paul at 

            God IS a weakly left-handed dice player

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