Apart from that, I think the last bit I need to do is to make the TensorProductFunctor inherit from MultivariateConstructionFunctor, to make coercion work for things like
sage: h = SymmetricFunctions(ZZ).h() sage: T = tensor([h, h]) sage: T.base_ring() Integer Ring sage: 1/2*T.an_element() (which currently raises TypeError: unsupported operand parent(s) for *: 'Rational Field' and 'Symmetric Functions over Integer Ring in the homogeneous basis # Symmetric Functions over Integer Ring in the homogeneous basis') Am I on the right track? Martin On Sunday 11 February 2024 at 12:34:44 UTC+1 Martin R wrote: > At https://github.com/sagemath/sage/pull/37220, I implemented a (simple > minded) construction functor for symmetric functions. > > The only major user visible change should be that > > sage: sZ = SymmetricFunctions(ZZ).s() > sage: sQ = SymmetricFunctions(QQ).s() > sage: sZ[1,1] + sQ[2] > s[1,1] + s[2] > > now works. This, and a little bit more, is what I need for my lazy > symmetric functions project. > > Under the hood, the pull request replaces `corresponding_basis_over` with > a proper construction functor which, however, follows the same spirit: > every basis of symmetric functions has to provide a description on how to > create it, by storing the appropriate method names. > > There is a todo note by Darij Grinberg from 2013 that this is an ugly > hack, and I agree, but nobody came up with anything better in the last 11 > years, so we might as well go with the idea which is working, at least for > the moment. > > There is one more uglyness I have to mention: I describe the functor as a > functor on the category of commutative rings, which is not true in > general. For example, for Macdonald polynomials, the functor really is > from the category of commutative rings with two distinguished elements. I > am guessing that creating a category RingsWithDistinguishedElements is a > bit much, and I wouldn't know how to do it. > > Comments (and, of course, also a review) would be greatly appreciated! > > Martin > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/15903b84-d2ce-4d04-bbe1-7eaeb92de627n%40googlegroups.com.
