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Re: Expressions with ellipsis (...)

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  • Subject: [mg93345] Re: Expressions with ellipsis (...)
  • From: magma <maderri2 at>
  • Date: Tue, 4 Nov 2008 06:19:35 -0500 (EST)
  • References: <gdmsbd$jv$> <>

On Nov 2, 7:58 am, AES <sieg... at> wrote:
> In article <geh9sa$fb... at>, dch888 <dch... at>
> wrote:
> > > Another answer is that Mathematica *should* understand the syntax
> > > with ellipsis-- and indeed it can with the facilities of David Park's
> > > Presentations application package.
> One has to be careful about the use and interpretation of ellipses.
> For example the Mathematica documentation for Compound Expression says
> that
>       expr_1 ;  expr_2 ;  =8A
>          evaluates the expr_i in turn, giving the last one as t=
he result.
> Would this statement, interpreted very literally using a precise
> definition of the ellipsis symbol, cover both
>       expr_1 ;  expr_2  ;  expr_3  ;  expr_4  ;
> and
>       expr_1 ;  expr_2  ;  expr_3  ;  expr_4
> or just one of these?  (Which one?)
> _Is there_ a precise definition of the ellipsis symbol? (in English, or
> in Mathematica)  
> Is " ;  " technically an expression? (in Mathematica)

The ellipsis symbol has no built-in special meaning in Mathematica. It is used
in CompoundExpression documentation in the same way it is used in

the semicolon ";" is NOT an "expression". It is just the INFIX form of
the CompoundExpression operator, exactly like "+" is the infix form of

CompoundExpression[a, b, c]

is equivalent to typing


(no semicolon at the end) and WILL display the value of c.
Instead typing


(semicolon at the end) is equivalent to typing

CompoundExpression[a, b, c;Null]

and WILL NOT  display the value of c. In both cases a, b and c are

I do not find this "mystical" or complicated in any way.
But for most Mathematica users, the semicolon can be simply considered a
separator between statements, like similar separators in other
Actually, to be more precise, the ";" is a "separator and suppressor
of output", while a simple carriage return (the big RETURN key in the
keyboard) is the basic separator between statements. You can see this
by typing


in the same cell, one below the other (using carriage return). In this
case the evaluations are carried out sequentially and the values are
displayed. The sequence of keypressees:

a "carriage return" b

is not interpreted as


or as

a multiplied by b

, but as

a and then b

So the carriage return is the pure separator of statements.

HOWEVER  ".."  (just 2 dots) HAS a built-in meaning as Repeated[] and
you can read what it means in the documentation

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