Re: [Maxima-discuss] use of subscripts, was: Yamwi (was: Construct sequence of identifiers)

[Stavros M. <mac...@gm...>]

I don't think the name matters much.
There is after all no standard name for a,b,c in x[a,b,c] independent of
both presentation and semantics. Subscript means that it appears below.
Index means that it indexes over some set. Then there's Einstein notation,
tensor contraction, etc.

                -s

On Sat, Jul 22, 2023 at 12:04 PM Robert Dodier <rob...@gm...>
wrote:

> On Sat, Jul 22, 2023 at 12:38 AM Wolfgang Hugemann <Au...@hu...>
> wrote:
>
> > Thanks for that hint. But in engineering subscripts are not always meant
> > as a variable index, but often serve as a means to distinguish
> quantities.
> >
> > If you denote the drag coefficient as c_d
> > (https://en.wikipedia.org/wiki/Drag_(physics)), you surely don't mean
> > c[d].
>
> Well, Maxima doesn't require subscripts to correspond to indices; instead
> a more general correspondence is allowed. In fact, subscripts can be any
> expressions, and there is no requirement that they form a complete set of
> anything. (Internally values assigned to subscripted variables are stored
> in a hash table.) In that sense, the subscript does indeed just serve as an
> indicator to distinguish conceptually-related quantities.
>
> Also of interest in this context, a recently-added feature (present in
> Maxima 5.44 and later) is that one can declare subscripts to be displayed
> above or below, before or after the base symbol. See
> declare_index_properties. E.g.:
>
> (%i11) declare_index_properties (FOO, [presubscript, presuperscript,
> postsuperscript, postsubscript]);
> (%o11)                        done
> (%i12) FOO[a, b, c, d];
>                               b   c
> (%o12)                         FOO
>                               a   d
>
>
> All the best,
>
> Robert
>
> PS. I see now that the function is misnamed; it should be called
> declare_subscript_properties. See, I got myself mixed up ... oh well!
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