Re: I think Omitting the multiplication sign is a big mistake

• To: mathgroup at smc.vnet.net
• Subject: [mg120256] Re: I think Omitting the multiplication sign is a big mistake
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Fri, 15 Jul 2011 04:08:55 -0400 (EDT)

```With current versions of Mathematica, of course, you get a
multiplication sign between adjacent numbers by default. And it's a
"real" multiplication sign -- the kind that looks like an x (no serifs)
-- and not the computerese * symbol.

On 7/14/11 9:19 PM, David Bailey wrote:
> On 14/07/2011 10:21, Murray Eisenberg wrote:
>> That's a wonderful example illustrating the difficulties of traditional
>> mathematical notation, the sort of thing that makes one appreciate why
>> so many students don't understand it. The fact that traditional math
>> notation was designed to handle single-letter variables with aplomb
>> makes thing even more confusing when students have to deal with
>> multi-character variables.
>>
>> A couple of programming languages have built on, among other things, the
>> principle that every operation must be explicitly indicated with a
>> symbol (so no space and no juxtaposition to denote multiplication). Such
>> of those languages that I know (APL and J) also abandon any hierarchy of
>> operators of the same kind, e.g., no precedence of multiplication over
>> addition (but they impose a different kind of precedence among
>> "functions" and "operators" or, as Ken Iverson later preferred to call
>> them, "verbs" and "adverbs" and "conjunctions").
>>
>>
>> On 7/13/11 3:11 AM, a boy wrote:
>>> In philosophical sense, to omit the multiplication sign is incorrect.
>>> Space-key or null is always describe the place of objects.
>>> A little student may think a(b+c)=ab+ac ==>    2(3+4)=23+24 ?
>>> In Mathematica, array[[n]]  puzzled almost all of new ones who never
>>> used the software.
>>>
>>
> Of course, you have to work quite hard using HoldForm to actually output
> the expression 2 3 + 2 4,so the problem is with input where two numbers
> are adjacent. I think an optional syntax restriction to require a "*"
> between two numbers, or else an error, might be quite useful.
>
> David Bailey
> http://www.dbaileyconsultancy.co.uk
>
>

--
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

```

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