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/651bb2f7-3267-47a9-9152-a44b6508fc57n%40googlegroups.com.
