Shaw was using the proposition to point to an inexpensive way to compute ~: / .* . +/ .* is extremely unlikely to ever be inexpensive.
----- Original Message ----- From: eesuk <[EMAIL PROTECTED]> Date: Monday, December 4, 2006 12:10 pm Subject: Re: [Jprogramming] monadic ~:/ . *. > On 12/5/06, Roger Hui <[EMAIL PROTECTED]> wrote: > > Regarding the proposition > > ((~:/ . *.) -: (2 | +/ . *)) A > > in your msg, I think you mean 2|-/ .* instead of > > 2|+/ .* . The latter expression +/ .* is the > > permanent which has been proven to the intractable > > (#P-complete; see the Wikipedia entry for > > "permanent"). > > (Sorry for my English) > > (2 | -/.*) -: (2 | +/ .*) , always true. > because 2&| == 2&|@- . > i.e determinant == permanent in GF(2) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
