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