Or accept the dictionary's specification of rank as a part of its definition...
Thanks, -- Raul On Fri, Jun 15, 2018 at 10:35 PM Henry Rich <[email protected]> wrote: > > It's a theorem: > > [x] >@(f each) y > > [x] >@(f&.>) y > > [x] >@((<@:f)&>) y > > [x] (>@(<@:f)&> y > > [x] (>@:<)@:f&> y > > [x] f&> y > > [x] (f every) y > > > Some of these steps are very much not obvious IMO. And you have to get > the rank of each right, that is, use the NuVoc definition of &. rather > than the Dictionary one. > > Henry Rich > > On 6/15/2018 8:30 PM, Ian Clark wrote: > > I've checked Chapter 1 off, but that's only to say I've checked out the > > code and verified it gives the results claimed. I didn't see it as my job > > to rewrite the treatment to make it clearer – which I can't do anyway > > without being sure what the author is trying to convey. > > > > I must confess that first section completely baffles me. I cannot see how > > to relate the "general rule" to actual examples of J code, although the > > article goes on to do just that … it seems. Does the "rule" represent real > > working J code? – even in a generic sense? Is it even true? (Theorems have > > to be true, but rules only have to be obeyed.) If it isn't always true, am > > I to understand it as a rule-of-thumb?And if it is in fact universally > > true, what procedure must I, the novice reader, follow in order to convert > > the "generics" into "specifics" to verify the fact? > > > > I'd be grateful for someone to cast light on the matter. Failing which, > > maybe I ought to remove my green checkmark, stand aside to let someone else > > scratch their head over it. > > > > On Sat, Jun 16, 2018 at 12:41 AM, David Lambert <[email protected]> > > wrote: > > > >> 50 Shades of j chapter 1 now says that rule is completely general. I'm > >> somewhat weak on j transformations and proofs, although what was there was > >> incorrect because of a counterexample: > >> > >> > >> every=.&> NB. uses compose > >> each=.&.> NB. uses under > >> rule =: (f every) -: >@(f each) > >> > >> NB. Is completely general? > >> > >> > >> thank you, Dave > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > --- > 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
