>Additionally you can ask J what the inverse for ,: is:
>
> ,: b. _1
>{.
Thanks for the reminder, Ric! We could warn people that this result
is not the ob/inverse function itself but just its linear representation.
Otherwise, a naive
(,: b. _1) i. 2 3 4
2 2 2
might disappoint quite a few people. The full story goes like this:
] hd =. ,: b. _1
{.
datatype hd
+-------+
|literal|
+-------+
$hd
2
hd i. 2 3 4 NB. You should be able to explain this by now:
2 2 2
(<hd) `: 0 i. 2 3 4
0 1 2 3
4 5 6 7
8 9 10 11
Martin
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