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

• To: mathgroup at smc.vnet.net
• Subject: [mg120242] Re: I think Omitting the multiplication sign is a big mistake
• From: David Bailey <dave at removedbailey.co.uk>
• Date: Thu, 14 Jul 2011 21:19:24 -0400 (EDT)
• References: <ivmcf3\$f8s\$1@smc.vnet.net>

```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

```

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