2 Jul
2002
2 Jul
'02
6:44 p.m.
David Feldman wrote:
In any category with products and coproducts one gets a map
n:(A+B)C ---> AxC + BxC .
In the category of sets this turns out an isomorphism, so we have our usual distributive law for cardinal arithmetic.
Surely this remains valid in an arbitrary topos, right?
It is even true in every cartesian closed category: For each object A the functor Ax_ has a right adjoint and therefore preserves colimits, in particular binary sums. Greetings Reinhard