Martin's solution is the correct one as it should be preparsing the input before it gets to the __init__(), which is then used as the key. This also is needed for HallLittlewood and Macdonald.
Best, Travis PS - Sorry for not responding sooner about this. On Tuesday, February 6, 2024 at 4:16:21 PM UTC+9 Martin R wrote: > Thank you for the explanation. > > I would be very surprised about `R.<t>=S.jack()`, because the > *coefficients* are (usually regarded as) rational functions in `t`, and the > *monomials* are Jack symmetric functions. > > I found the following alternative solution at > https://doc.sagemath.org/html/en/reference/structure/sage/structure/unique_representation.html > : > > class Jack(UniqueRepresentation): > @staticmethod > def __classcall__(cls, Sym, t='t'): > return super().__classcall__(cls, Sym, Sym.base_ring()(t)) > > def __init__(self, Sym, t): > > I think I like it better. Is there anything wrong with it? > On Monday 5 February 2024 at 19:17:20 UTC+1 Nils Bruin wrote: > >> I second that response. More specifically, what you're running into is: >> >> sage: S.jack(t=t) == S.jack(t='t') >> False >> >> which is indeed within UniqueRepresentation design parameters: returned >> values are cached on construction parameters 't' and '"t"' hash to >> different values. If you need better processing, you'd need to normalize >> the input parameters further before calling the UniqueRepresentation >> constructor. In your case, I think jack.Jack (which is what ends up being >> called) actually does expect a string. Perhaps this keyword should be >> renamed to "names" to comply with uses elsewhere? e.g., would >> R.<t>=S.jack() make sense? If so, then the following should probably be >> made to work: >> >> sage: preparse("R.<t>=S.jack()") >> "R = S.jack(names=('t',)); (t,) = R._first_ngens(1)" >> On Monday 5 February 2024 at 05:57:40 UTC-8 Martin R wrote: >> >>> At https://github.com/sagemath/sage/pull/37220 I am trying to provide a >>> construction functor for symmetric functions. I am hitting the following >>> bug, which I hope is easy to fix if one knows the right magic: >>> >>> sage: P.<t> = QQ[] >>> sage: S = SymmetricFunctions(P) >>> sage: S.jack().P() == S.jack(t=t).P() >>> False >>> >>> Can someone help me out? >>> >>> 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/63adb36b-d809-47d0-a98f-6cf3f70508acn%40googlegroups.com.
