2019-09-12 13:43:16 -0500 | asked a question | bug in basis or family? I am having trouble dealing with modules with infinite bases and I think I pin-pointed the issue to the fact that there are no checks on elements belonging on a family. I am not sure if this is a feature of Sage or a bug so I'll accept any explanation on this. An example will clarify the issue:
So I am not sure I can trust any code I'm writing with `CombinatorialFreeModule` cause I can make those checks, but I will have to go over the source to see if every method that I am calling makes these checks. Somehow if this is a feature I should get a warning or something in the docs isn't it? |

2019-09-11 09:12:25 -0500 | commented answer | Restriction of scalars for free modules Perhaps, I don't understand, which object is an instance of |

2019-09-10 12:56:22 -0500 | asked a question | Restriction of scalars for free modules Suppose I have a free module And |

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2019-09-06 04:43:55 -0500 | answered a question | implement algebras with some extra structure What I found was the easiest is to define my parents as inheriting from the corresponding objects from This way I don't even need to implement an element class and I can focus on morphisms which is the only thing that changes in this category. |

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2019-09-03 14:05:43 -0500 | asked a question | implement algebras with some extra structure I seem not to be understanding the way to implement categories with extra structure. Suppose I want to implement the category Now from reading the examples in https://doc.sagemath.org/html/en/refe... or https://doc.sagemath.org/html/en/them... I could set up And that woul d give me a canonical forgetful functor But instead of implementing those methods I would want to use the methods of the underlying parent of Finally I have similar concerns about implementing |

2019-09-03 08:00:03 -0500 | answered a question | Change degree in InfinitePolynomialRing For what it's worth, you can force degree(x_n) = n+1 with the patch I opened a ticket in https://trac.sagemath.org/ticket/28452 |

2019-09-02 14:34:50 -0500 | answered a question | is an object of a subcategory an object of the ambient category? I'll add an answer in case someone finds something similar. I am new to sage so I suppose there's something silly that I am doing and there are better ways of implementing this. It turns out that And now |

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2019-09-02 11:22:25 -0500 | asked a question | is an object of a subcategory an object of the ambient category? I have defined a category The omitted code I think its irrelevant. I can check that Now I create a parent of And I can check that these parents are objects of Where can I be making a mistake?
But at least I get |

2019-08-31 14:51:59 -0500 | asked a question | Viewing a Derivation as a linear endormorphism I have a ring R over the rational numbers and a Derivation D of R. I want to view D as a linear endomorphism of R over Q. I tried these two methods. First the obvious one Then I figured I could try to make a linear transformation explicitly out of D: So finally I tried to coerce R into a vector space over Q |

2019-08-29 05:30:20 -0500 | asked a question | Virasoro Verma module Basis Hi I am starting to look at the implementation of the Virasoro algebra and some of its modules in https://doc.sagemath.org/html/en/refe... I have a question regarding the method basis() that returns a basis of the module. As the following example shows this particular linear combination of basis elements is zero so I wander in which sense are we getting a basis or a generating set, or even better how to actually get sage to recognize that the combination is actually zero?
` ` |

2019-08-28 11:07:56 -0500 | commented answer | How to get the graded part of a graded ring? Thanks for the reply, I had seen another question with this answer. What I ended up doing is implementing the same basis(n) method from the source code of GradedCommutativeAlgebra in my quotient ring because I couldn't change the degrees. |

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2019-08-28 10:46:02 -0500 | commented answer | weighted univariate polynomials Thanks a lot this is precisely what I needed. I had tried (2,) before but not explicitly adding the ,1, |

2019-08-28 07:03:57 -0500 | commented question | weighted univariate polynomials That doesn't work for a number of other reasons, I have a particular derivation of degree 1 and doubling the degrees is not an option. I need a number of methods from PolynomialRings and Groebner bases that I cannot coalesce to GradedCommutativeAlgebra and a few more. But still it's striking why that example as in my question is implemented the way it is |

2019-08-27 13:55:48 -0500 | asked a question | weighted univariate polynomials I have a polynomial algebra in n variables k[x_1,...,x_n]. I know how assign different degrees to each of the generators as in However if I want to do this with only one variable this does not work I wander if I can do this in an uniform way cause I need to use a class that takes an arbitrary number of variables. |

2019-08-27 09:19:11 -0500 | commented question | How to get graded component of graded ring my question was closed as duplicate, but I have been looking quite a bit in ask.sagemath.org and couldn't find the same question. I found similar questions like for freely generated rings only. |

2019-08-27 08:34:06 -0500 | asked a question | How to get the graded part of a graded ring? I have a graded quotient of a graded polynomial ring, say something like I would like to get the vector space over QQ consisting on vectors of degree, say 9, in Q. |

2019-08-27 08:32:45 -0500 | asked a question | How to get graded component of graded ring I have a graded quotient of a graded polynomial ring, say something like I would like to get the vector space over QQ consisting on vectors of degree, say 9, in Q. |

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2018-10-30 08:02:19 -0500 | commented question | compute first (and only first) values of Hilbert function There is no previous definition of 'x' and I is a generic homogeneous ideal Ideal (x_11^3 + ... ) of Multivariate Polynomial Ring in x_11, x_21, x_31, x_12,..., x_26, x_36 over Rational Field. |

2018-10-26 01:42:32 -0500 | asked a question | compute first (and only first) values of Hilbert function I have an homogeneous ideal (say $I$) and I'm interested in computing the first few values of the Hilbert function. I undestand that doing something like does give me this, but this seems to require computing the whole Hilbert series which blows up for my problem quickly. Is there a way of getting the first few values without computing the whole thing? |

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2018-10-24 12:38:41 -0500 | asked a question | Change degree in InfinitePolynomialRing If I use Assuming any of the orderings 'lex, deglex, degrevlex' I will have $z_0 < z_1 < z_2 < ... < y_0 < y_1 < ... < x_0 < x_1 < ...$ And each variable having degree 1. I would like to obtain something like 'deglex' but assigning degree $n$ to $x_n,y_n,z_n$ so that in particular I would obtain $z_0 < y_0 < x_0 < z_1 < y_1 < x_1 < ... $ Is there a way to implement this. It seems that in order to compute Grobner bases on arc schemes these orderings are much more natural that the ones implemented, but I just started looking at Sage so I may have missed the right implementation of polynomial rings in infinitely many variables to work. |

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2018-10-24 12:21:59 -0500 | commented answer | formal series over InfinitePolynomialRing Thanks, I've been using the first sum as in your post and more or less I can get by doing some computations up to each order. |

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2018-10-24 10:37:04 -0500 | asked a question | formal series over InfinitePolynomialRing I apologize if the question does not belong here. This is my first try to using sage and I find the documentation hard to read/search. I am trying to work with symbolic power series over a non-Noetherian ring. So for example I have: And I'd like to consider the series $f(t) = \sum x_n t^n$ as an element of R. But my first try I'll appreciate any help or if you can point me to the documentation where to read about this. |

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