Ralf, On Thu, Jun 10, 2010 at 6:40 PM, Ralf Hemmecke <[email protected]> wrote: > ... > With the definition of > > Module(R:CommutativeRing): Category == BiModule(R,R) > add > if not(R is %) then x:%*r:R == r*x > > I think, it is quite sufficient when > > SquareMatrixCategory(ndim,R,Row,Col): Category == Definition where > Definition ==> Join(DifferentialExtension R, BiModule(R, R),_ > ... > > which is the current definition. >
Ok. >> If it did, then I think the question of coercion would be moot. > > But note, my question was about looking for an appropriate operation * > (or rather an appropriate coercion) so that > > R and SquareMatrix(2,Fraction R) > > can be connected. > That was not clear to me. And in fact such a coercion does seem to be applied in the case R = Integer. > As written in > http://groups.google.com/group/fricas-devel/browse_thread/thread/63f43b33d26ecb6d > , Fraction R and SquareMatrix(2, Fraction R) is not a problem. > Sorry I did not notice when you originally pointed this out. Now I see the difference between (97) and (100) but the computation seems oddly out of order. So I guess I must go back and try to understand again why the result is a DirectProduct in your example. Why is there no automatic coercion when R = Polynomial(Complex Integer))? Is this some limitation of Fraction? Regards, Bill Page. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/fricas-devel?hl=en.
