nope, booleans means 1+1=1. take + as OR and * as AND in the propositional calculus.
the key thing is to compute the reachability matrix of a digraph. an awkward way to do it would be by computing the power series A+A^2+\dots +A^n, where n is the #vertices and A adjacency matrix, and replace every nonzero element by 1. but i would like to take A over the booleans right from the begining. thanks pedro On 14 Maio, 13:20, [EMAIL PROTECTED] wrote: > David Joyner wrote: > > On Wed, May 14, 2008 at 6:29 AM, Pedro Patricio <[EMAIL PROTECTED]> wrote: > > >> hi all... i am sure you can easily help me with this one. > > >> how can i define a matrix over the booleans? i know this is trivially > >> done over ZZ and so forth. > > > If by booleans you mean GF(2), then just replace ZZ by GF(2) in the > > construction you know over ZZ. Is that what you meant? > > Also, if you already have a matrix, you can convert it to a matrix over > GF(2) by doing: > > m.change_ring(GF(2)) > > Jason --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sage-edu" group. To post to this group, send email to sage-edu@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-edu?hl=en -~----------~----~----~----~------~----~------~--~---
