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