There is a proof of a very similar theorem in section 1.4 of *Notation as a Tool of Thought <http://www.jsoftware.com/papers/tot.htm>*. (The difference is that index origin is 1 in the paper.)
On Thu, Jun 6, 2013 at 6:44 AM, Raul Miller <[email protected]> wrote: > Caution: this code can give an incomplete result. For example, I do > not believe it will find 'aabaab'. Rather than fix this, I'll defer to > other solutions in this thread (which I imagine properly address this > issue). > > If anyone wants to take this code and fix it, the first instance of 2 > -~/\ ] should be replaced with a mechanism that treats all > combinations of 2 (and not just adjacent pairs). > > (And on that note, I Tracy Harms recently directed my attention to a > page with a beautiful proof that 2&! is +/@i. - that concept would be > useful, here, I think. I wish I had recorded the url of that page. But > the gist of my thought is that it should be possible to go from y and > a member of i.2!y to a unique pair of two numbers in the range i.y, > and that might be a nice way of implementing this "combinations of 2" > function.) > > FYI, > > -- > Raul > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
