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Re: RE: Re: Sometimes <space> means multiple

  • To: mathgroup at
  • Subject: [mg75423] Re: [mg75364] RE: [mg75358] Re: Sometimes <space> means multiple
  • From: Murray Eisenberg <murray at>
  • Date: Sun, 29 Apr 2007 03:14:26 -0400 (EDT)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <>
  • Reply-to: murray at

Why "mistake"?  Why not allow Mathematica to mimic as much of 
traditional mathematical notation as possible without running into 
genuine ambiguity?

After all, it's really convenient to be able to use 2 Exp[x] and Cos[2 
t] -- and even 2Exp[x] and Cos[2t] -- without having to insert an extra, 
distracting multiplication symbol.  Then the usage in 2 4, for example, 
just extends that.

In my own work, I ordinarily include an explicit multiplication symbol 
-- and I prefer the multiplication sign one gets from Esc * Esc instead 
of the FORTRANish * -- when the factors are numbers.  There's nothing to 
prevent you from doing that if you don't like the implicit 
multiplication indicated by a space.

Virgilio, Vincent - SSD wrote:
> Personally, I think it was a mistake to overload the meaning of "space"
> to multiply. I bet Wolfram Inc. would reverse that decision now, if it
> wasn't for backward compatibility.
> I like to compare Mathematica to C++. Somewhere in his writings, Bjarne
> Stroustrup mentions the same issue, and his decision not to overload
> whitespace. I think the question also arises on the Boost mailing lists
> now and then, mostly tongue-in-cheek.
> (Corrections welcome.)
> Vince Virgilio
> -----Original Message-----
> From: Bill Rowe [mailto:readnewsciv at]
> Sent: Thursday, April 26, 2007 3:35 AM
> To: mathgroup at
> Subject: [mg75364] [mg75358] Re: Sometimes <space> means multiple , sometimes not
> On 4/25/07 at 5:27 AM, siewsk at wrote:
>> As a newbie, I was taught that <space> character in Mathematica means
>> multiple. But sometimes it does not.
>> For example:
> <examples snipped>
> Mathematica allows spaces to be placed before or after any operation.
> Consequently, a space is only interpreted as a multiply when there is no
> other operator or other possible interpretation.
> So, -4 -2 is the same as -4 - 2 or -4-2 and gives -6 but
>      -4 (-2) will yield 8
> --
> To reply via email subtract one hundred and four
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Murray Eisenberg                     murray at
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

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