What is the definition of "partitioning modifier"? Thanks,
-- Raul On Mon, Dec 27, 2021 at 9:40 AM Henry Rich <[email protected]> wrote: > > The partitioning modifiers (u/ u/\ etc.) can create several pleasing > identities that don't hold for cyclic gerunds. > > The key insight is that u"n is a partitioning modifier. It is the > simplest one, the one where partition=cell. > > This was not understood when J was defined. u"n is defined to do two > things: partitioning and assigning a rank for combining purposes. > > The other partitioning modifiers have rank _ . If u"n had been defined > to have combining rank _, symmetry would be preserved. > > And, we wouldn't need @: . u@(v"n) would do what @: does now. > > OTOH, we would need a new primitive to assign combining rank, for the > cases where that's needed (especially for names). > > It goes without saying that no one is suggesting that these changes > should go into the J language. > > Henry Rich > > On 12/26/2021 4:54 PM, Raul Miller wrote: > > On Sun, Dec 26, 2021 at 2:53 PM Henry Rich <[email protected]> wrote: > >> You meant to use rank 0. > > Ah, I see... > > > > Sadly, this defeats the concept of rank, breaking a simple identity > > involving rank and functions: > > > > F=:*:`]"0 > > (F -: F"F) ,~3 > > 0 > > > > That problem would go away if the cyclic mechanism had been deployed > > on items within the given rank rather than items selected by the rank. > > > > I wish I had noticed this sooner. > > > > But I guess maybe sometimes there just aren't any good options... > > > > Thanks, > > > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
