On Jun 09, Matthias Koeppe wrote:
See [1]https://trac.sagemath.org/ticket/19448
With the patch in this ticket I find this: sage: V = CombinatorialFreeModule(QQ, Partitions()) sage: M = V.submodule([V.an_element()]) sage: M.reduce(V.an_element()) 0so far so good.
sage: v = V([3,2,1]); v B[[3, 2, 1]] sage: M.reduce(v) Traceback (most recent call last): ... ValueError: tuple.index(x): x not in tupleWithout this patch but forcing the orders as in my previous e-mail this worked:
sage: P = Partitions() sage: V = CombinatorialFreeModule(QQ, P) sage: V._order = P.rank sage: V._rank_basis = P.rank sage: M = V.submodule([V.an_element()], already_echelonized=True) sage: v = V([3,2,1]); v B[[3,2,1]] sage: M.reduce(v) B[[3,2,1]] sage: M.reduce(V.an_element()) 0So I suppose the quotient could be implemented in some cases. Is the above ValueError expected with this patch?
Best,
R.
On Tuesday, June 9, 2020 at 2:43:04 PM UTC-7, Reimundo Heluani wrote: I am trying to reuse the code already in place in combinat/freemodule and modules/with_basis/subquotients to construct a finite dimensional submodule of an infinite dimensional one. I think that there are places where the basis of the ambient space is assumed to be a list without needing it. The following is a minimal example of what I mean: sage: RPT = PartitionTuples(level=4) sage: V = CombinatorialFreeModule(QQ, RPT) sage: M = V.submodule([V.an_element()], already_echelonized=True) sage: M.lift(M.an_element()) Traceback (most recent call last): ... NotImplementedError: cannot list an infinite set However this can be forced into working by simply: sage: V._rank_basis = RPT.rank sage: V._order = RPT.rank sage: M.lift(M.an_element()) 2*B[([], [], [], [])] + 6*B[([], [1], [], [])] + 2*B[([], [1], [2], [3])] + 4*B[([1], [], [], [])] The exception is being raised because V._order is set to None and the first call to get_order simply forces it to be self.basis().keys().list() which fails on an infinite set. A call to set_order() would also fail, because it sets correctly self._order but then it calls rank_from_list on it to produce self._rank_basis. I haven't tested much but it seems that just setting these two orders correctly in the infinite set I can produce a working finite dimensional submodule without trouble. This must be something that has arisen before, so perhaps someone here can point me to some part of the library which deals with these situations? Best, R. -- 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 [2]sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit [3]https://groups.google.com/d/msgid/ sage-devel/1a6a6a07-99f7-4d42-8516-6ba212088ca1o%40googlegroups.com. References: [1] https://trac.sagemath.org/ticket/19448 [2] mailto:sage-devel+unsubscr...@googlegroups.com [3] https://groups.google.com/d/msgid/sage-devel/1a6a6a07-99f7-4d42-8516-6ba212088ca1o%40googlegroups.com?utm_medium=email&utm_source=footer
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