On Sun, 6 Apr 2008, Anne Archibald apparently wrote: > I am not aware of any algorithm for finding inverses, or > even determining which matrices are invertible, in the > peculiar Boolean arithmetic we use.
Again, it is *not* peculiar, it is very standard for boolean matrices. And with this behavior, a nonnegative integer power has an obvious graph theoretic interpretation. Such boolean matrices are obviously invertible if they are orthogonal. It turn out this is a necessary condition as well. [1]_ Orthogonality is obviously easy to test. Cheers, Alan Isaac .. [1] Luce, D., 1952, "A Note on Boolean Matrix Theory", Proceeding of the Am. Math. Soc 3(3), p.382-8. _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
