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MathGroup Archive 2007

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

  • To: mathgroup at smc.vnet.net
  • Subject: [mg75500] Re: [mg75474] Re: [mg75442] Re: [mg75426] Re: [mg75423] Re: [mg75364] RE: [mg75358] Re: Sometimes <space> means multiple
  • From: János <janos.lobb at yale.edu>
  • Date: Thu, 3 May 2007 03:46:09 -0400 (EDT)
  • References: <200704270918.FAA23598@smc.vnet.net> <200704290714.DAA21234@smc.vnet.net> <200704300738.DAA22373@smc.vnet.net> <200705010719.DAA07230@smc.vnet.net> <200705020751.DAA05016@smc.vnet.net>

Just to be sure I looked up Jen=F6 Erd=F6s selected teachings again at

http://www.math.klte.hu/~szekely/Jeno11.pdf

and found no usage of "space" or "asterix" or "star" in any shape or 
form there for multiplication.  I could see only nothing or the 
central point for multiplication.

So when someone is claiming that the virtuosity of Mathematica to 
convert "a b" into "a*b" and vice verse is the best thing after 
sliced bread, I am not impressed.

With the best,

J=E1nos
P.S.  If you can read Hungarian, you will find that the pdf listed 
above is one of the finest work a real mathematician ever produced.


On May 2, 2007, at 3:51 AM, Andrzej Kozlowski wrote:

> I think I can see some advantages to "intellectual laziness". It
> might, for example, stop people writing long posts when they have no
> point to make.
>
> So to make it short: it was already pointed by someone else that
> Mathematica's use of "space" for multiplication is simply the 
> nearest =
>
> approximation to using nothing at all - by far the most common
> convention in algebra. Mathematica does allow "nothing" to be used
> when  no ambiguity results; in other cases space is used, which
> approximates rather well what one can see in books an d papers on
> algebra.
> In InputForm asterisk is used because central dot is not available 
> in =
>
> ASCII and ordinary dot is used, naturally, for dot product. Asterisk
> is sometimes used in books on algebra do denote binary operations,
> probably more often than "x" (which can, of course,  be used in
> TraditionalForm in Mathematica).
> Intellectual laziness (presumably due to infection) prevents me from
> writing any more on this subject.
>
> Andrzej Kozlowski
>
>
> On 1 May 2007, at 16:19, J=E1nos wrote:
>
>> I think the reason for "space" used as multiply is the typical anglo-
>> american intellectual laziness :)  /Old Hungarian proverb:  "Whose
>> shirt it is not, should not take it on"/
>>
>> Steve just did not want to type an extra character when he came up
>> with the design - that is it.  He was also constrained by the ASCII ==

>
>> 7 =
>>
>> bit.
>>
>> If I look back on my education for multiplication in elementary
>> school a dot was use on the "middle of the lane".  On a Mac it is
>> <Option>+<Shift>+<9>.
>>
>> Now to use that would have been more painful than just <Shift>+<8>,
>> wouldn't it ?.
>>
>> The <Shift>+<8> came to the math circles via computers and with
>> punch =
>>
>> cards where the restrictive ASCII 7 bit ruled the world and "a" and
>> "b" had to be tightened with SOMETHING.
>>
>> Looking many professional journal pdfs one thing is sure.  Neither
>> the "space" nor the "star" is used for multiplication.  It is still
>> the dot on the "middle of the lane", a small "x" or nothing.  That
>> is, I never see "a*b" or "a b" as a multiplication of a and b but
>> rather I see "ab" or "a=B7b".
>>
>> With the best,
>>
>> J=E1nos
>> P.S.  If I take the "a b" to its ultimate test and "try" it in pre-
>> fix " ab" or post-fix "ab " that shows clearly the dumbness of the
>> usage of space in its pure naked form :)
>>
>> On Apr 30, 2007, at 3:38 AM, Andrzej Kozlowski wrote:
>>
>>> I compltely agree. I also think that any comparisons between C++ and
>>> Mathematica in this respect are completely off the mark, unless of
>>> course sombody decides to develop an analogue of "TradtitionalForm"
>>> for C++.
>>>
>>> I would also like to point out the following obvious but not
>>> insignificant fact. Enter  a b (or 2 3  if you prefer) and 
>>> convert to
>>> InputForm. You will obtain an explicit asterisk in place of the
>>> space. Conversely, enter a*b and convert to TraditionalForm (or even
>>> StandardForm). You will get a space instead of the asterisk. 
>>> This, in
>>> my opinion,  is exactly how it should be. In fact, I am somewhat
>>> shocked that anyone would claim otherwise.
>>>
>>> Andrzej Kozlowski
>>>
>>>
>>> On 29 Apr 2007, at 16:14, Murray Eisenberg wrote:
>>>
>>>> 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 sbcglobal.net]
>>>>> Sent: Thursday, April 26, 2007 3:35 AM
>>>>> To: mathgroup at smc.vnet.net
>>>>> Subject: [mg75364] [mg75358] Re: Sometimes <space> means
>>>>> multiple , sometimes not
>>>>>
>>>>> On 4/25/07 at 5:27 AM, siewsk at bp.com 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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>>>>>
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>>>>>
>>>>> and do not necessarily represent those of ITT Corporation. The =
>>>>>
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>>>>> *
>>>>> =0D
>>>>>
>>>>
>>>> --
>>>> 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
>>>>
>>>
>>
>>
>>
>> ----------------------------------------------
>> Trying to argue with a politician is like lifting up the head of a
>> corpse.
>> (S. Lem: His Master Voice)
>>
>>
>



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