[sage-combinat-devel] Re: Image of a permutation

On 2020-03-08, David Joyner wrote: > On a tangential matter, I'd like to add that > according to Dan Bump's notes "Group Representation > Theory" (http://sporadic.stanford.edu/bump/group/gr1_4.html), > this set of elements that the permutations does not > fix is called the support. Exactly. >

[sage-combinat-devel] Re: Image of a permutation

On 2020-03-08, David Joyner wrote: > I agree with Michael O, a permutation is a bijection, > so the image is the domain is the codomain. +1 > For a patch to "define the image of a permutation > to be the set of elements that it does not fix" is a > mistake, IMHO. Maybe the set computed could be

[sage-combinat-devel] Re: fast vector partitions algorithm

, Simon On 2020-02-13, Simon King wrote: > Hi Denis, > > in the past, sage-combinat-devel was a very active list and certainly > the topic of your post fits well, but it seems to me that it would be a > good idea to re-post on sage-devel. > > Did you read the developer's guide? &

[sage-combinat-devel] Re: fast vector partitions algorithm

Hi Denis, in the past, sage-combinat-devel was a very active list and certainly the topic of your post fits well, but it seems to me that it would be a good idea to re-post on sage-devel. Did you read the developer's guide? Certainly people could help you contributing the code. In particular

[sage-combinat-devel] Re: Categories, Parents, Elements

Hi Bruce, On 2018-05-19, Bruce wrote: > Can I make two comments? > i. I think it would be better to say that (to a first approximation) a sage > category is a subcategory of Sets. > When you are taught category theory it is drilled into you not to think of > an object

[sage-combinat-devel] Re: Categories, Parents, Elements

Hi Travis, On 2018-05-19, Travis Scrimshaw wrote: >> And "parent" is just another word for "object of a sub-cateogory of the >> category of sets". So, if there is a category of tableaux and if each >> tableau has elements, then a tableau is a parent and its elements are,

[sage-combinat-devel] Re: Categories, Parents, Elements

Hi Bruce, On 2018-05-18, Bruce wrote: > As I understand it, in sage, the way to implement this is to have a > category. Provided that what you are implementing does in fact form a mathematical category (https://en.wikipedia.org/wiki/Category_(mathematics)) > However

[sage-combinat-devel] Re: Improvements to FreeAlgebra

Hi Travis, On 2017-03-31, Travis Scrimshaw wrote: > I agree that this is something that should be fixed (actually 0 is not > recognized as being in a CFM, which is a bug IMO). AFTER the fix from #22707? > Well, we do have a number of CFM subclasses that explicitly have a

[sage-combinat-devel] Re: Improvements to FreeAlgebra

Hi Nicolas, On 2017-03-29, Nicolas M. Thiery wrote: > It would be interesting to know specifically on which aspects the path > algebra is improving on the current free algebra. The data structure > of indices (i.e. words in the generators)? The data structure for >

[sage-combinat-devel] Improvements to FreeAlgebra

Hi! Just to make people aware: 9 years ago, it was decided to override Parent.__contains__ for CombinatorialFreeModule, thus working around Sage's coercion framework. I guess we should try to remove the custom CombinatorialFreeModule.__contains__, which is why I created #22707 (the branch hasn't

[sage-combinat-devel] Re: ClonableIntArray

Hi Andrew, On 2016-03-16, Andrew wrote: > I want this functionality too. I tried adding: > > __metaclass__ = ClasscallMetaclass > > but this produces the error: > > TypeError: Error when calling the metaclass bases > metaclass conflict: the metaclass of a derived

Re: [sage-combinat-devel] How to compute the orbits?

Hi Nicolas! Am Montag, 29. Februar 2016 17:03:08 UTC+1 schrieb Nicolas Borie: > > sage.combinat.enumeration_mod_permgroup contains tools to enumerate > integer vectors modulo the action of a permutation group. > Sure, that's where I was looking, and also I reviewed part of the code, IIRC. >

[sage-combinat-devel] How to compute the orbits?

Hi! I have a finite set C, and I have a finite group that acts on the n-fold Cartesian product of C by permutation of positions, wher n is a fixed number. At sage.combinat.enumeration_mod_permgroup, I see how I can compute the orbit of one element of the n-fold Cartesian product of C. But how

[sage-combinat-devel] CombinatorialFreeModule relies on implementation details of elements

Hi! Working on path algebras, which inherit from CombinatorialFreeModule, I found that CombinatorialFreeModule makes specific assumptions on implementation details of the elements of a module. What I mean is, for example, CombinatorialFreeModule.sum. It relies on the assumption that all

[sage-combinat-devel] Re: CombinatorialFreeModule relies on implementation details of elements

Hi Nicolas, On 2015-08-26, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: So far CombinatorialFreeModule has been meant as a concrete implementation of a ModulesWithBasis, with a specific data structure for its elements. Seriously? Then please do grep CombinatorialFreeModule) -R src/sage

[sage-combinat-devel] Re: Code duplication

Hi again! Bump... On 2015-07-15, Simon King simon.k...@uni-jena.de wrote: Hi! Working at #18897, I just noticed that we not only have a presumably rather fast boilerplate implementation of binary trees in sage.misc.binary_tree, but we also have a high-level implementation

[sage-combinat-devel] Re: Code duplication

On 2015-07-22, Simon King simon.k...@uni-jena.de wrote: Hi Nathann, On 2015-07-22, Nathann Cohen nathann.co...@gmail.com wrote: +1 to that. This being said, do you know if it is used anywhere? That code has been written in 2007 and has not seen any serious improvement since. As it is quite

[sage-combinat-devel] Re: Code duplication

Hi Nathann, On 2015-07-22, Nathann Cohen nathann.co...@gmail.com wrote: +1 to that. This being said, do you know if it is used anywhere? That code has been written in 2007 and has not seen any serious improvement since. As it is quite lacking on the documentation side, perhaps we could just

[sage-combinat-devel] Re: How do I implement subalgebras?

Hi Salvatore, I forgot to answer: On 2015-07-17, Salvatore Stella etn45...@gmail.com wrote: One other question (this one maybe more git related): suppose I want to have both your ticket in my code before I start my modifications; one way to do it would be to create a new branch and merge in

[sage-combinat-devel] Re: How do I implement subalgebras?

Hi Salvatore, On 2015-07-17, Salvatore Stella etn45...@gmail.com wrote: One thing that is not clear to me is why should I inherit from sage.structure.element.Element rather than sage.structure.element.CommutativeAlgebraElement; shouldn't I get _mul_ and _add_ for free in this way? Well,

[sage-combinat-devel] Re: How do I implement subalgebras?

Hi Salvatore, On 2015-07-16, Salvatore Stella etn45...@gmail.com wrote: I browsed a little though sage documentation for examples of how to construct subalgebras but I could not find anything appropriate. Do you have suggestions/ideas on which is the correct way to implement this? Relevant

[sage-combinat-devel] Code duplication

Hi! Working at #18897, I just noticed that we not only have a presumably rather fast boilerplate implementation of binary trees in sage.misc.binary_tree, but we also have a high-level implementation in sage.combinat.binary_tree that is totally orthogonal to the available boilerplate code. The

[sage-combinat-devel] Re: weird behavior under combining remove and for loop

Hi Anne, On 2015-06-28, Anne Schilling a...@math.ucdavis.edu wrote: Is this what I should expect from this code: sage: positions=[1,2,3,4,5,6] sage: for j in positions: : positions.remove(j) : sage: positions [2, 4, 6] Shouldn't I expect the empty list at the end? Of course,

[sage-combinat-devel] Re: weird behavior under combining remove and for loop

On 2015-06-28, Darij Grinberg darijgrinb...@gmail.com wrote: On Sun, Jun 28, 2015 at 10:07 AM, Nicolas Borie pout...@gmail.com wrote: PS: The last entry of my collection of Python tricky codes was danger from free variables : (MAKE A LIST OF FIRST POWER FUNCTION (1, X, X^2, X^3, X^4)) L =

[sage-combinat-devel] Re: Symmetric functions --- HopfAlgebras(...) or not?

Hi Anne, On 2015-06-27, Anne Schilling a...@math.ucdavis.edu wrote: Is it not the case that sage: a.parent() 5-bounded Symmetric Functions over Fraction Field of Univariate Polynomial Ring in t over Rational Field in the 5-Schur basis forms a ring? Or at least a magma? That

[sage-combinat-devel] Symmetric functions --- HopfAlgebras(...) or not?

Hi! The following is a problem for my work at #18758, which aims at making arithmetic operations faster that are defined via category element/parent classes: sage: Sym = SymmetricFunctions(FractionField(QQ['t'])) sage: ks3 = Sym.kschur(3) sage: ks5 = Sym.kschur(5) sage: a =

[sage-combinat-devel] Re: Test digraph for cycles containing a vertex?

Hi Nathann, On 2015-06-22, Nathann Cohen nathann.co...@gmail.com wrote: I would imagine this would be relatively efficient: Do not use that. If you want to figure out if there is a path from u to v, compute the distance (or a shortest path) between the two. Thank you! I thought that

[sage-combinat-devel] Re: Test digraph for cycles containing a vertex?

Hi Nathann, On 2015-06-22, Nathann Cohen nathann.co...@gmail.com wrote: Indeed. And a BFS is cheap. Do you need it to be very very fast? If it is for your path algebras, then it can probably be written very low at backend level. Probably that won't be needed. At some point I need to know if a

[sage-combinat-devel] Re: Specification of combinatorial free module?

Hi Nicolas, On 2015-06-22, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: I checked the documentation and code, and indeed it's ambiguous. The index set is really meant to be a parent; for example there are tests such like I in Sets().Finite() and the dimension method calls `cardinality`.

[sage-combinat-devel] Re: Specification of combinatorial free module?

Hi Nicolas, On 2015-06-21, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: On Sat, Jun 20, 2015 at 01:38:10PM +, Simon King wrote: I think it would be nice if CombinatorialFreeModule.Element would actually use Sage's coercion framework. Is there a ticket to make

[sage-combinat-devel] Re: Specification of combinatorial free module?

Hi Nicolas, On 2015-06-21, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: (Combinatorial)FreeModule(K, I) is about constructing the free module M over the base ring K, with a basis (b_i)_{i\in I} indexed by I. Exactly. This is what I thought it would do. And the point is: Undocumented

[sage-combinat-devel] Specification of combinatorial free module?

Hi! In order to create a right module over a path algebra P, with a vector space basis given by the potentially infinite family of paths starting at some vertex, I thought I'd start with CombinatorialFreeModule. My expectation was that it would work *easily* and out of the box, if - one provides

[sage-combinat-devel] Re: Test digraph for cycles containing a vertex?

Hi Travis, On 2015-06-19, Travis Scrimshaw tsc...@ucdavis.edu wrote: Hey Simon, That is correct and the only way I know of AFAIK. Thank you! Cheers, Simon -- You received this message because you are subscribed to the Google Groups sage-combinat-devel group. To unsubscribe from this

[sage-combinat-devel] Re: Test digraph for cycles containing a vertex?

Hi Nicolas, On 2015-06-20, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: - search for a path from one of the out neighbors of v to v Sure, but how? In fact I was looking for a method of digraphs telling me whether there is a path from vertex v to vertex w, but I couldn't find one. w in

[sage-combinat-devel] Re: Specification of combinatorial free module?

PS: I think it would be nice if CombinatorialFreeModule.Element would actually use Sage's coercion framework. Is there a ticket to make CombinatorialFreeModule.Element a Cython class using the infrastructure that is provided by sage.structure.element.ModuleElement? Best regards, Simon -- You

[sage-combinat-devel] Test digraph for cycles containing a vertex?

Hi! Let D be a digraph, potentially with multiple edges and loops. Let v be a vertex. How should one test whether v is contained in a cycle (including loops)? Is it correct that v is in a cycle or loop if and only if (len(D.strongly_connected_component_containing_vertex(v))1) or (v in

[sage-combinat-devel] Re: How to set the category of finite Coxeter groups properly?

Hi Christian, On 2015-06-04, Christian Stump christian.st...@gmail.com wrote: Should Category of finite groups still be there? Failed example: FiniteCoxeterGroups().super_categories() Expected: [Category of coxeter groups, Category of finite groups, Category of finite

[sage-combinat-devel] Re: Sage Days in Chicago

Hi! On 2014-03-11, Anne Schilling a...@math.ucdavis.edu wrote: Aaron Lauve and Peter Tingley are planning to host Sage Days in Chicago during the summer of 2015 (not 2014!!). This will focus on representation theory, crystals, and combinatorics. When does it take place? Best regards,

[sage-combinat-devel] Re: [sage-devel] Re: quiver algebra

Hi Nicolas, On 2014-07-12, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: Shouldn't it be the job of CombinatorialFreeModule to provide a generic iterator, relying on the iterators over the base ring and the indexing set for the basis? This is currently missing. Yes. Or probably

[sage-combinat-devel] Re: About nested functions not showing up in the doc

Hi Nathann, On 2014-06-11, Nathann Cohen nathann.co...@gmail.com wrote: A 4 years old ticket whose last comment is 10 months old ? Cool to see that this is being solved. If I recall correctly, I am (one of the) author(s). However, the ticket ran against a limitation of LaTeX that made it

[sage-combinat-devel] Re: redesign combinatorial statistics

Hi Vincent, On 2014-05-28, Vincent Delecroix 20100.delecr...@gmail.com wrote: A method ( = a Python function) is not a Sage Map ( = a Python object that model a mathematical function). I would like first to convert the method into a map Which is trivially possible, see

[sage-combinat-devel] Re: redesign combinatorial statistics

Hi Christian, On 2014-05-28, Christian Stump christian.st...@gmail.com wrote: -- Can I turn any method in Sage which mimics a mathematical function into a map in the above sense? To put it differently: Is it right that there are always (or almost always) parents available to use as domain and

[sage-combinat-devel] Re: redesign combinatorial statistics

Hi Christian, On 2014-05-28, Christian Stump christian.st...@gmail.com wrote: But how am I then convincing someone knowing that information to add that information there? Ask him/her to put @combinatorial_map in front of the method in question. In other words, there should be no need to change

[sage-combinat-devel] Re: redesign combinatorial statistics

Hi Paul, On 2014-05-28, Paul-Olivier Dehaye paul-olivier.deh...@math.uzh.ch wrote: Two comments: - Nathann is arguing that no empty methods/classes should be present. Is he? Sorry, then this is a point where Nathann and I do not agree. I find abstract methods useful. I thought that his main

[sage-combinat-devel] Re: [sage-devel] redesign combinatorial statistics

Hi Viviane, On 2014-05-27, Viviane Pons vivianep...@gmail.com wrote: The way it works: the decorator replaces the tagged methods by instances of combinatorial map class, the functions only checks which methods are indeed instances of this class. And, if I understand correctly, it is this kind

[sage-combinat-devel] Re: [sage-devel] redesign combinatorial statistics

Hi Nathann, On 2014-05-27, Nathann Cohen nathann.co...@gmail.com wrote: I'm trying to find the best way of doing it. The decorator seems the best way to flag. Before returning the orignal function, I could store the map itself. But I would like to create the map objects only if needed, and

[sage-combinat-devel] Re: [sage-devel] redesign combinatorial statistics

Hi Paul, On 2014-05-27, Paul-Olivier Dehaye paul-olivier.deh...@math.uzh.ch wrote: Dead right ! Is there any reason why gathering this semantic information requires this decorator to wrap the function in a combinatorial map ? Can't the information be gathered wherever we need it *without*

[sage-combinat-devel] Re: [sage-devel] redesign combinatorial statistics

Hi Paul, On 2014-05-27, Paul-Olivier Dehaye paul-olivier.deh...@math.uzh.ch wrote: For anyone involved in findstat, there are several layers of complexity. This is my assessment from outside the findstat collaboration: - they also deal with Mathematica code - they also deal with

[sage-combinat-devel] Re: [sage-devel] redesign combinatorial statistics

Hi Viviane, On 2014-05-27, Viviane Pons vivianep...@gmail.com wrote: What I have in mind (and I think what Nathan had in mind) is def map_decorator(f, args): # storing the info return f Yes, exactly! Currently, storing the info means wrap f, encode the information by the colour of

[sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi Nathann, On 2014-05-20, Nathann Cohen nathann.co...@gmail.com wrote: I do not want to concatenate compositions. I want to sum the integers that a composition contains. I was mistaken in my previous post. Not sum() is a Python builtin, but add(). So, why do you insist on using sum() instead?

[sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi Nathann, On 2014-05-20, Nathann Cohen nathann.co...@gmail.com wrote: I have no idea what you are talking about. I was talking about the (Python builtin?) function sum(), and I don't think it makes use of Combination.sum(). Sorry, I mean Composition, not Combination. And

[sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi Nathann, On 2014-05-20, Nathann Cohen nathann.co...@gmail.com wrote: What the hell is add ? I did not even know this thing existed ! It is a Python builtin, in contrast to sum, which is defined somewhere in sage.misc. We have to make sum work too. That's the standard Python function to

Re: [sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi all, Am Dienstag, 20. Mai 2014 11:50:30 UTC+2 schrieb Vincent Delecroix: More fun: there are occurrences of sum(self) in the file compositions.py. But here this sum is intended to actually sum the elements. It is fine, because preparser is turned off and sum is the builtin sum there!

[sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi Darij, On 2014-05-20, Darij Grinberg darijgrinb...@gmail.com wrote: Or is add() a Sage alias for sum() ? It seems that Sage's add() is an alias for Python's sum(), and at the same time Sage overrides Python's sum() by a function with a slightly different semantics. And how exactly does

[sage-combinat-devel] Re: sum(Composition([1,2,3])) # broken

Hi Nicolas, On 2014-05-19, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: That being said, since Composition seems to be the single combinatorial object having a sum method, we could think of renaming it to something more appropriate that would not conflict with Sage's sum syntax and

[sage-combinat-devel] Re: CombinatorialFreeModule

Hi! On 2014-05-16, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: By the way: usually an element class need not inherit from UniqueRepresentation Often enough an element class *should* not inherit from UniqueRepresentation, as UniqueRepresentation means that the resulting instances will be

[sage-combinat-devel] Re: About _element_constructor_ of CartesianProduct

On 2014-04-29, Nathann Cohen nathann.co...@gmail.com wrote: I checked it out; at first glance, the issue is that element_constructor returns a tuple not an instance of the cartesian product. I can commit a fix in an hour or so. I wrapped it with self(tuple ...) before, and it only produced

[sage-combinat-devel] Re: [sage-devel] Re: Call for vote about ticket #10963: axioms and more functorial constructions

Hi Paul, hi Mark, On 2014-03-12, Mark Shimozono msh...@math.vt.edu wrote: Instead, I would advocate using a declarative domain specific language built for semi-formalizing mathematics The appeal of this paradigm is evident. It addresses a fundamentally important issue: how to structure

[sage-combinat-devel] Re: Call for vote about ticket #10963: axioms and more functorial constructions

Hi Nicolas, On 2014-03-12, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: - The specification of an axiom `A` currently goes in the documentation string of the method Cs().A, where Cs is the category defining that axiom ... and where one should note that Cs().A is *not* obtained

[sage-combinat-devel] Re: Call for vote about ticket #10963: axioms and more functorial constructions

Hi Travis On 2014-03-11, Travis Scrimshaw tsc...@ucdavis.edu wrote: I've been using #10963 in developing #14901 (Lie algebras). I first gave 'Lie' as an axiom of NonAssociativeNonUnitalAlgebras (which I just asked Nicolas for how to do it without really looking at the examples), Good to

[sage-combinat-devel] Re: Tensors on free modules of finite rank

Hi John, On 2014-03-10, John H Palmieri jhpalmier...@gmail.com wrote: Longer question/comment (not directed at you, but at the general situation in Sage): is it a problem to have multiple parallel developments of free modules, Is it a problem to have a multitude of different implementations

[sage-combinat-devel] Re: [sage-devel] Re: Call for vote about ticket #10963: axioms and more functorial constructions

Hi Nathann, On 2014-03-07, Nathann Cohen nathann.co...@gmail.com wrote: sage: P = Parent(category=Cs().Finite()) sage: P.foo() # ok, nice I am a method on finite C's sage: P.is_finite() # Where does that come from? True Is this method named 'is_finite' because the axiom's

[sage-combinat-devel] Re: tensor products of free modules; combinatorial algebras

Hi Mark, On 2014-02-19, Mark Shimozono msh...@math.vt.edu wrote: What if two classes coming from different categories (neither inheriting from the other) share a method name, and both apply to the same instance? Which method would get invoked? Each parent P knows its category, say, C. But

[sage-combinat-devel] Re: Sage-Combinat Days 2014

Hi! On 2013-12-03, Adrien Boussicault bouss...@labri.fr wrote: Dear Sage-Combinat lovers, We are thinking about organizing new Sage-Combinat days in February-May. Sorry, I somehow missed to put my preferred dates into the doodle quest soon enough. Yesterday I did, but I reckon it is too

[sage-combinat-devel] Re: Dear Poset Users, tell me what you like

Hi Darij, On 2013-12-30, Darij Grinberg darijgrinb...@gmail.com wrote: On another note: I remember the __init__ of Poset (well, FinitePoset) being way slower than it reasonably should be. I think this is related to it ducktyping the input (which IMHO is a bad thing anyway but seems standard

[sage-combinat-devel] Re: Nathann vs Categories

Hi Nathann, On 2013-12-25, Nathann Cohen nathann.co...@gmail.com wrote: sage: F23 = IntegerModRing(23) sage: F23.category().is_subcategory(Fields()) True You mean False. sage: F23 in Fields() True sage: F23.category().is_subcategory(Fields()) True Only now it is True. For this reason,

[sage-combinat-devel] Re: SymmetricFunctions(QQ).kschur() -- removing deprecated code (#5457)

Hi Darij, On 2013-12-22, Darij Grinberg darijgrinb...@gmail.com wrote: sage: Qt = PolynomialRing(QQ, 't') sage: t = Qt.gen() sage: SymmetricFunctions(Qt).kschur(3) 3-bounded Symmetric Functions over Univariate Polynomial Ring in t over Rational Field in the 3-Schur basis Now this, of

[sage-combinat-devel] Re: sage-combinat move to git

Hi! Meanwhile I got convinced that the change to git and the use of the new Sage development scripts is mostly a very good thing. My advice would be: Look at what the development scripts do. Some of them answer questions you asked. I am only a bit sceptical in one aspect of git resp. the

[sage-combinat-devel] Re: sage-combinat move to git

Hi Nicolas, On 2013-11-04, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: - Switching from one branch to the other. As Simon pointed out, this will be easy. However whether it's practical or not will depend on how much time we will have to wait for recompilation in average. Part of

[sage-combinat-devel] Re: Usage of the term Composition

Hi Anne, [Followup-To: nach gmane.comp.mathematics.sage.devel gesetzt.] On 2013-10-21, Anne Schilling a...@math.ucdavis.edu wrote: With regard to `Composition`, I do not have any strong feelings. I do not see anything wrong with having both `IntegerComposition` and `Partition` in the

Re: [sage-combinat-devel] Re: Usage of the term Composition

[Followup-To: nach gmane.comp.mathematics.sage.devel gesetzt.] On 2013-10-21, Nils Bruin nbr...@sfu.ca wrote: The issue is that when Composition gets imported into the global namespace, the context is lost and you end up with a routine that has a rather ambiguous name. +1 Global namespace

[sage-combinat-devel] Re: Inversion of matrix...

Hi Nicolas, On 2013-09-03, Nicolas Borie nicolas.bo...@univ-mlv.fr wrote: For now : *** sage: SF = SymmetricFunctions(QQ).schur() sage: Id = identity_matrix(SF, 2); Id [s[] 0] [ 0 s[]] sage: Id.inverse() Traceback (most recent

[sage-combinat-devel] Re: Inversion of matrix...

PS: On 2013-09-03, Simon King simon.k...@uni-jena.de wrote: Shouldn't there always be a coercion from the base ring into a unital algebra? It seems to me that the underlying problem is that matrix spaces do not properly use the new coercion model (in particular, they define their own __call__

[sage-combinat-devel] Reviewer for #12630 (quivers and quiver algebras)?

Hi! At SD 49, we made good progress on #12630 (Add representations of quivers and quiver algebras to sage). We would have needed perhaps two additional days to finish everything, but it seems that we lost momentum. Please, if someone interested in quiver algebras is reading this, I'd appreciate

[sage-combinat-devel] Re: Should ClasscallMetaclass do a consistency test?

Hi Volker, On 2013-08-01, Volker Braun vbraun.n...@gmail.com wrote: The surprise factor that a function returns a differently-named class is a lot less than the surprise you get when something that looks like a class constructor call gives you a completely unrelated instance, that is

[sage-combinat-devel] Re: Should ClasscallMetaclass do a consistency test?

Am Sonntag, 28. Juli 2013 14:23:39 UTC+2 schrieb Simon King: It turns out that a lot of stuff in sage.combinat breaks. Apparently some people really want that if C is a class then C(*args,**kwds) is not an instance of this class. Here is an example: sage: mu = PartitionTuple([3,2]) sage

[sage-combinat-devel] Towards using Parent.__call__ in Homset.__call__

Hi! Currently, Homset.__call__ has nothing to do whatsoever with Parent.__call__. In particular, it won't to assign a certain Morphism baseclass to an attribute Element---which would be the way to proceed in the case of a Parent. But Homset *is* a Parent, by definition of the class! Hence, do

[sage-combinat-devel] Quiver algebras: Should the invalid path be *equal* to zero?

Hi! I am about to fix some further issues with quivers, their representations and algebras (namely: I'd like that TestSuite(...).run() passes) at #12630. One problem: Each quiver has an invalid path, which is currently mapped to a non-zero element in the algebra of that quiver, but this non-zero

[sage-combinat-devel] Re: Quiver algebras: Should the invalid path be *equal* to zero?

Hi Volker, On 2013-07-12, Volker Braun vbraun.n...@gmail.com wrote: How about 3. Disallow invalid paths as paths and path algebra elements. No way. Otherwise, the algebra would only have a partially defined multiplication, which makes it not an algebra. Best regards, Simon -- You

[sage-combinat-devel] Re: Quiver algebras: Should the invalid path be *equal* to zero?

PS: On 2013-07-12, Simon King simon.k...@uni-jena.de wrote: Hi Volker, On 2013-07-12, Volker Braun vbraun.n...@gmail.com wrote: How about 3. Disallow invalid paths as paths and path algebra elements. No way. Otherwise, the algebra would only have a partially defined multiplication

[sage-combinat-devel] Re: groupoids

Hi Vincent, On 2013-07-04, Vincent Delecroix 20100.delecr...@gmail.com wrote: What I want to do is to define the set of paths in a graph Directed graph aka quiver? Then you might look at #12630, which is makign progress towards being ready for review (which would be followed by a Cython version

[sage-combinat-devel] Re: groupoids

Hi Vincent, On 2013-07-04, Vincent Delecroix 20100.delecr...@gmail.com wrote: Is there in #12630 a class Paths built as a groupoid ? The class Paths is of course only for the *elements* of a whatever-name-we-attribute-to-it. There has recently been a discussion in this list, and it was agreed

[sage-combinat-devel] Re: docstrings and overloaded methods

Hi Darij, On 2013-06-29, Darij Grinberg darijgrinb...@gmail.com wrote: thanks. This comes too late for my patch, but I'll think about it in the future (I didn't think about splitting the summary into a one-line and a detailed part). If I recall correctly, each doc string is supposed to be of

[sage-combinat-devel] Re: docstrings and overloaded methods

Hi Darij, On 2013-06-28, Darij Grinberg darijgrinb...@gmail.com wrote: here's a quick question: I'm defining some method on a class and then redefining it on a subclass for speed improvement. (Concretely, it is a map on the symmetric functions which I redefine on the power-sum basis because

[sage-combinat-devel] Re: combinatorial map decorators

On 2013-06-20, Nathann Cohen nathann.co...@gmail.com wrote: What I claim is that you can make all this work without making Sage compute things that are only necessary for find_stat, even when find_stat is not what the users want to use. You can do so by adding information to the docstrings,

[sage-combinat-devel] Re: Need help defining a class with parent EnumeratedSets whose init take a list

Hi Prasad, On 2013-06-14, Amritanshu Prasad amripra...@gmail.com wrote: I am trying to define a class with parent EnumeratedSets whose constructor takes a list as an input. First of all, EnumeratedSets is a category. So, I suppose you mean: You try to define a parent in the category of

[sage-combinat-devel] Algebra associated with a magma or monoid?

Hi! If F is a (free associative) magma, for example given by a quiver, then F.algebra(QQ) is supposed to return the QQ-algebra over F. However, F.algebra(QQ) currently just returns a Combinatorial Free Module, and multiplication of its elements is not available. Are there patches on trac which

[sage-combinat-devel] Re: Algebra associated with a magma or monoid?

Hi Nicolas, On 2013-05-14, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: Are there patches on trac which would make F.algebra(QQ) return an actual algebra? Yes, the dreaded functorial construction patch! Then I wonder what to do with #12630 (quiver representations and so on). It does

[sage-combinat-devel] Should SmallFreeCategory of a quiver be implemented as a category?

Hi! This is another design question related with quiver representations and algebras. By #14535 (needs review), there is support for immutable graphs. Hence, one can use an immutable digraph as a key for a unique representation of all stuff we plan to do on top of quivers. At #12630, Frédéric

[sage-combinat-devel] Re: Should SmallFreeCategory of a quiver be implemented as a category?

Hi Nicolas, On 2013-05-06, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: On Mon, May 06, 2013 at 01:33:27PM +, Simon King wrote: Or do you think this would be over-engineering? Would you prefer, if Q is an immutable digraph, that FreeSmallCategory(Q) just returns a parent

[sage-combinat-devel] Re: Do we want to have the category of associative magmas?

Hi all, I hope I summarise the discussion correctly: - There is no mathematical difference between a quiver and a digraph. Hence, there will be no separate sub-class Quiver of DiGraph. - How shall we call the algebraic structure formed by the paths in a quiver? PathMonoid? PathMagma?

[sage-combinat-devel] Re: Do we want to have the category of associative magmas?

Hi Nicolas, On 2013-05-01, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: I definitely see your point about not multiplying the number of classes for no reason. The executive summary of the rant below is: I am very happy with your proposal; just don't call the parent of the paths Quiver

[sage-combinat-devel] Re: Do we want to have the category of associative magmas?

On 2013-04-29, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: I would tend to keep them separate; a quiver and its sets of paths are different mathematical objects. It would be weird to ask for: sage: path in quiver whereas this is natural: sage: path in quiver.paths() By

[sage-combinat-devel] Do we want to have the category of associative magmas?

Hi! Currently, I try to resume writing code for modules over finite dimensional path algebra quotients. At #12630, Jim Stark proposes some code that apparently has a non-empty intersection with what I need, but much of it is orthogonal. So, I'm seeking advice how to fit my experimental code with

[sage-combinat-devel] Re: Do we want to have the category of associative magmas?

Hi Nicolas, On 2013-04-29, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: First question: Would you agree that a quiver should be identified with the algebraic structure formed by paths with concatenation? Or should quiver as a digraph be kept separate from quiver as an algebraic

[sage-combinat-devel] Re: How to solve this combinatorial problem in Sage?

Hi Gary, On 2013-04-22, Gary McConnell garymako...@googlemail.com wrote: I kind-of went quiet on this because Nicolas was way ahead of me :) but (obviously only if you have time) I would be fascinated to hear how you resolve this because I have some not dissimilar problems in finite field

[sage-combinat-devel] Re: How to solve this combinatorial problem in Sage?

Hi Nathann, On 2013-04-23, Nathann Cohen nathann.co...@gmail.com wrote: Well, here's the thing if you did not work it out already : With Sage's MILP support, you will be able to answer easily those two questions : Is there a subcollection of sets that partition your point set ? What is the

[sage-combinat-devel] Re: How to solve this combinatorial problem in Sage?

Hi Marco, On 2013-04-21, mmarco mma...@unizar.es wrote: The linear combinations that have some zero coefficient are the intersections of the corresponding subspace with the coordinate hyperplanes. That is, the set of bad linear combinations is a subset of codimension 1. The generic elements

[sage-combinat-devel] Re: How to solve this combinatorial problem in Sage?

Hi Nicolas, On 2013-04-16, Nicolas M. Thiery nicolas.thi...@u-psud.fr wrote: For non exact covers, this can be formulated straightforwardly as a Mixed Integer Linear Program (MILP): take a 0-1 variable y_S for each set S, and an inequation $\sum_{S, x\in S} y_S \geq 1$. So the problem can be

[sage-combinat-devel] Re: How to solve this combinatorial problem in Sage?

Hi Gary, On 2013-04-15, Gary McConnell garymako...@googlemail.com wrote: I'm struggling a little to understand what the programming bottleneck is in all this. Clearly you do not want a completely naive search as you said above; but are the 'tests' of the f_i on each m expensive in time, and is

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