> "range" is the term I learned in school for what some people call the
> "codomain".  It's represents the set of results which a function can
> produce.

I see, I think you are referring to the image of the domain because
the codomain can be arbitrary.  At any rate, I usually do not care
about the images of the domains when comparing verbs because if the
domains and the mappings are the same then the images of the domains
ought to be the same.

> It's arguably a bug because [something seems to be missing here].  That said, 
> there are two possible ways
> the bug can be identified:

> a) It's a bug because the result of +:@*: d. 1 has infinite rank while
> the dictionary says that +:@*: is being treated as if it has zero rank

> b) It's a bug because we should never use the result of d. at any rank
> other than 0.


My simple minded guess is that the implementation of d. regarding (@)
and (@:) works reasonably well, although the rank change from 0 to _
seems arbitrary, but it stumbles for (at) and ([:),

   (u @ v)f. d.1
[
   (u at v)f. d.1
["0 0 0
   (u @ v)f. d._1
0 0 0 1r6&p.
   (u at v)f. d._1
|domain error
|       (u at v)f.d._1

   (u @: v)f. d.1
[
   ([: u v)f. d.1
[
   (u @: v)f. d._1
0 0 0 1r6&p.
   ([: u v)f. d._1
|domain error
|       ([:u v)f.d._1

On Sat, Jan 12, 2013 at 9:35 PM, Raul Miller <[email protected]> wrote:
> It's arguably a bug because.  That said, there are two possible ways
> the bug can be identified:
>
> a) It's a bug because the result of +:@*: d. 1 has infinite rank while
> the dictionary says that +:@*: is being treated as if it has zero rank
>
> b) It's a bug because we should never use the result of d. at any rank
> other than 0.
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