The cheat sheet is a really nice summary. Thanks for taking the time to put that together.
-Steven On 3 May 2014, at 22:10, Jose Mario Quintana <[email protected]> wrote: > Personally, I find illuminating to rewrite (functionally) equivalent verbs > in J. Thus, one can rewrite the dyadic bonding form (X&u) as (X&u@[^:[) and > the hook (u v) as ([ u v@]). Moreover, symbolic verbs and nouns provide a > visualization and confirmation of tautologies. > > > NB. Symbolic verbs and nouns... > > u=. ('('"_ , 'u '"_ , ] , ')'"_) :('('"_ , [ , ' u '"_ , ] , ')'"_) > :.(('('"_ , 'u^:_1 '"_ , ] , ')'"_) :('('"_ , [ , ' u^:_1 '"_ , ] , ')'"_)) > v=. ('('"_ , 'v '"_ , ] , ')'"_) :('('"_ , [ , ' v '"_ , ] , ')'"_) > :.(('('"_ , 'v^:_1 '"_ , ] , ')'"_) :('('"_ , [ , ' v^:_1 '"_ , ] , ')'"_)) > 'X Y'=. 'X' ; 'Y' > > u Y > (u Y) > X u Y > (X u Y) > > v inv Y > (v^:_1 Y) > X v inv Y > (X v^:_1 Y) > > > NB. Bond (dyadic form), (X&u) -: (X&u@]^:[) ... > > (i:999) ( X&u -: X&u@]^:[ ) Y > 1 > > (i:3) X&u Y > (X u^:_1 (X u^:_1 (X u^:_1 Y))) > (X u^:_1 (X u^:_1 Y)) > (X u^:_1 Y) > Y > (X u Y) > (X u (X u Y)) > (X u (X u (X u Y))) > > (i:3) X&u@]^:[ Y > (X u^:_1 (X u^:_1 (X u^:_1 Y))) > (X u^:_1 (X u^:_1 Y)) > (X u^:_1 Y) > Y > (X u Y) > (X u (X u Y)) > (X u (X u (X u Y))) > > > NB. Hook, (u v) -: ([ u v@]) ... > > ( (u v) -: ([ u v@]) ) Y > 1 > > X ( (u v) -: ([ u v@]) ) Y > 1 > > > (u v) Y > (Y u (v Y)) > X (u v) Y > (X u (v Y)) > > ([ u v@]) Y > (Y u (v Y)) > X ([ u v@]) Y > (X u (v Y)) > > > Of course, matching symbolic verbs does not necessarily imply a general > equivalence ; for example, the ranks of the verbs must be considered. > > > Anyway, these and other tautologies are on page three of the cheatsheet at > http://www.2bestsystems.com/foundation/j/patches/j%20cheatsheet.pdf > > > PS. J experts: I would appreciate if you point out any errors that you > might find. > > > > On Sat, May 3, 2014 at 1:47 PM, Joe Bogner <[email protected]> wrote: > >> On May 3, 2014 1:33 PM, "Alex Giannakopoulos" <[email protected]> >> wrote: >>> >>> Just FYI. >>> I thought you might like the insight into the workings of the mind of a >>> noob, since you went to all that trouble to help... >>> >>> >> >> I am glad you asked. I didn't know the answer until working through it. >> >> I assume it's like a class or like customer satisfaction -- for every one >> person that asks a question there is probably 4 wondering the same thing >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
