Ralf, What does the following have to do with Monoid?
On Thu, Jun 10, 2010 at 1:06 PM, Ralf Hemmecke <[email protected]> wrote: > On 06/10/2010 06:33 PM, Bill Page wrote: >> Ralf, >> >> I think that the map >> >> coerce : Fraction Polynomial Complex Integer -> % >> >> which is apparently x+-> [x,x] >> >> in >> >> )sh DirectProduct(2,Fraction Polynomial Complex Integer) >> >> should not be called a coercion. > > > From DirectProduct ... > > if R has Monoid then > 1 == new(dim, 1)$Vector(R) pretend % > u : % * r : R == map(x +-> x*r, u) > r : R * u : % == map(x +-> r*x, u) > x:% * y:% == [x.i * y.i for i in 1..dim]$Vector(R) pretend % > > That makes sense. > > Well... automatic coercion cannot always be right. > There is such a thing as being too automatic - especially when the results are unintuitive and of limited utility. 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.
