Moving this to chat as this seems quite a way from programming. I prefer to use p. as well. But when I saw the original forum question it got me to remembering trying to do proofs tacitly. I should have tested the statements using J. But one should be able to do this without such a crutch. I struggle doing proofs using tacit expressions instead of explicit expressions like I did in high school algebra and trig. It seems that somehow it ought to be as easy but for some reason I make serious mistakes like this one.
Then there is the thought that intrigues me as I try. There's always the approach to write a verb to test each line of the proof with various arguments which would have caught this error. There might even be a way to write a verb which will verify the correctness of each step. And maybe even one that would generate the steps get from one statement to another thus generating a proof or show that a conjecture is false. In doing proofs I used various proven identities to transform one statement to another. We have such identities implied in the J dictionary and from mathematics like associative, commutative and distributive. Applying them seemed as a mechanical process but there seemed to be a bit of art in choosing identities to use. So far I'm stumped. On Wed, Aug 19, 2009 at 8:17 AM, Raul Miller <[email protected]> wrote: > On Wed, Aug 19, 2009 at 10:12 AM, Zsbán Ambrus<[email protected]> wrote: > > ([^2:)+(2**)+(]^2:) > > ((2^~[)+(2**)+(2^~])) > > (^&2...@[+(2**)+^&2...@]) > > (*:@[+(2**)+*:@]) > > Note that these are not equivalent (the first > one gives a different result than the later > examples). > > (When I am simplifying tacit expressions, I > always like to include a representative > argument so I can have the machine catch > simple mistakes.) > > That said, personally, I like using p. for polynomials. > > FYI, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
