[sage-devel] Re: Weber polynomials

2016-03-06 Thread David Kohel
Hi, To extend beyond a pre-computed database, I suggest linking the cm library of Andreas Enge: http://www.multiprecision.org/index.php?prog=cm Pari has implementation of the weber function, but I think this (cm) should be the reference implementation, in the framework of standard mpc/mpfr lib

[sage-devel] Re: Catalog of algebras: the definition of an algebra

2015-05-07 Thread David Kohel
Hi All, I think it would be a good idea to have a subcategory of associative algebras (and inheritance of classes from an associative class). Morphisms need to know to check associativity. On the other hand, I was convinced years ago (by an argument of Bergman at Berkeley) that algebras shou

[sage-devel] Sage compilation

2022-06-12 Thread David Kohel
stallation/conda.html but it fails with the error message below (another path problem?). The config log file is attached. Any suggestions would be appreciated. --David Kohel Checking whether SageMath should install SPKG gmp... checking gmp.h usability... yes checking gmp.h presence... no configur

[sage-devel] Fwd: [sage-algebra] Boundary cases

2013-03-04 Thread David Kohel
In a ring of characteristic 0, it seems that 0^0 (= 1) is well-defined. In my view this is correct. It makes it much simpler to define the matrix (e.g. FF a finite field): G = matrix([ [ a^i for a in FF ] for i in range(k) ]) However, in finite fields or any of the the following rings, 0^0 giv

Re: [sage-devel] Re: Products of permutations use nonstandard order of operation

2013-07-16 Thread David Kohel
Hi, I also strongly support both left and right actions, with the syntax Left action: s1(s2(x)) == (s1*s2)(x) Right action: (x^s1)^s2 == x^(s1*s2) Currently the left (functional) notation is implemented in Sage with the right order of application: s1(s2(x)) == (s2*s1)(x) is True. This need

[sage-devel] Re: calculus in SAGE/SymPy

2007-09-12 Thread David Kohel
Hi, Just to add my 2 bits, I think we should aim for something like the following: sage: x = var('x') sage: X = x.domain() sage: X Affine line over the Real Field sage: X.identity() x sage: f = sin(x) sage: X == f.domain() True sage: f = sin(domain=X,codomain=X) sage: y = var('y') sage: g = sin(

[sage-devel] Re: LLL

2007-09-21 Thread David Kohel
Since LLL and LLLGram in Magma V2.13 are written by Damien Stehle, using his asymptotically better algorithm. The previous version was not even mathematically correct (adhoc "improvements" or post-processing could destroy the LLL reduction condition). Damien provides C code under GPL and can be

[sage-devel] Re: Proposed minor enhancement: elliptic curve transformations

2007-09-23 Thread David Kohel
Hi John, I would strongly suggest that this construction be compatible with isogenies (also yet to be implemented). Thus one should be able to compose isomorphisms and isogenies with one another. Moreover, one should be able to access the defining polynomials -- this is useful to verify the def

[sage-devel] Re: Proposed minor enhancement: elliptic curve transformations

2007-09-25 Thread David Kohel
Hi John, > > Group --> WierstrassIsomorphismGroup > > GroupElement --> WeierstrassIsomorphism > > OK I'll try that. On this subject, I had the idea that an Iso(X,Y) subset of Hom(X,Y) should be defined for every category. Note that the subset Aut(X) of an End(X) is a group, but in general the W

[sage-devel] Re: non-commutative polynomial rings

2007-10-27 Thread David Kohel
Hi, I didn't implement subs for these types, but it seems to be inheriting from some generic code. The description of output says that self is returned if the substitution fails, which is the behavior you observe. This could be fixed by defining subs for a FreeAlgebraElement, but the logic of t

[sage-devel] Re: inner product of complex vectors

2008-01-10 Thread David Kohel
Dear John (et al.), I think the inner product should be the same irrespective of the field. The inner product as dot product is relevant to the study of quadratic forms, conics, and orthogonal groups. For instance finding a rational point on the conic x^2 + y^2 + z^2 = 0 over CC is equivalent t

[sage-devel] Multiple return values

2008-01-16 Thread David Kohel
There was a thread on multiple return values coming from Magma, since renamed to "Integer points on conics" William pointed out that one can access the multiple return values using nvals: x = magma.XGCD(15, 10) x,y,z = magma.XGCD(15, 10, nvals = 3) The first returns an integer, while the seco

[sage-devel] Sollya

2008-01-16 Thread David Kohel
Here is another open source CAS, which is being advertised here. Someone might want to evaluate it to see how much is being reinvented and what is new. Note that it uses a particular French open source licence designed in response to the GPL and which supposedly addressed legal problems with the

[sage-devel] Re: Multiple return values

2008-01-17 Thread David Kohel
Hi, Agreed that Magma > I'll just come out and say it -- It's a _terrible_ design in Magma. +1. > Yet another example of the Magma semantics being a pain. > They don't even use a notion of None. Argh. +1 ; Although there is a syntax to denote no argument (return x, _;) The problem is that in

[sage-devel] Re: Multiple return values

2008-01-18 Thread David Kohel
> I will try to take all the above on board as I am implementing it, and > look forward to having you people make constructive criticisms > But David K's suggestion about the set of all iso/automorphisms might > wait until the next round. I (or someone else) can implement the structures of Is

[sage-devel] Re: generator inconsistencies in finite fields

2008-01-21 Thread David Kohel
Hi, It is probably a bias of the choice of (additive) generators for finite field extensions which results in the primitive field element also being a generator for the multiplicative group (confusingly called a "primitive element of the finite field"). It is not possible to set GF(q).gen() to a

[sage-devel] Re: generator inconsistencies in finite fields

2008-01-23 Thread David Kohel
Hi All, Just a few comments: there are three possible concepts for generator[s]: 1) As a field over its prime field or base field (function gen(), category Field or Algebra); 2) As a vector space over its base field (function additive_generators(), category Module) 3) As a group, restricted to t

[sage-devel] Re: Why is the Groebner basis not an ideal

2008-01-25 Thread David Kohel
> OK, as a conscious decision it is certainly justified. Of course, > mathematically you are right that an object and a particular basis of > that object are two different things. Only i was surprised, because i > grew up with Singular and not with Magma... FYI, magma has both commands GroebnerBa

[sage-devel] Re: Permutation vs PermutationGroupElement

2008-02-12 Thread David Kohel
Hi Mike, Thanks for the explanation. Indeed a Permutation could be represented by an element of a symmetric group, but we would want to make sure that until a group-theoretic question is asked, no call to GAP should interfere with the calculations. Your: sage: G = Permutations(3) would be ana

[sage-devel] Re: discrete logs

2008-02-14 Thread David Kohel
Hi, I find this discussion interesting since this was a project I proposed for magma, implemented by Paulette Lieby. The idea was to take any finite abelian group G, create a wrapper A = GenericAbelianGroup(G), passing in various parameters: magma> GenericAbelianGroup; Intrinsic 'GenericAbelian

[sage-devel] Re: discrete logs

2008-02-16 Thread David Kohel
Hi John, > I'm not sure I understand the end of your message. Nowhere does the > code I have in mind assume that anything is cyclic, let alone of prime > order: the bsgs and dlog functions will terminate if there is no > solution, with a ValueError. Since baby-step, giant-step is deterministic

[sage-devel] Strings in SAGE

2007-01-04 Thread David Kohel
I'd like to get opinions on the following from the experts -- I am in the process of preparing for a cryptography course, for which I've previously used a Magma package that I wrote and would like to use SAGE. Python has some special octal ('\ooo') and hexadecimal ('\xhh') string constructors, e

[sage-devel] Re: Strings in SAGE

2007-01-05 Thread David Kohel
OK, I've created the following: sage: S = BinaryStrings() sage: S Free binary string monoid sage: (x,y) = S.gens() sage: x '0' sage: y '1' sage: x^7 * y^11 * x^17 * y^2 '000111011' sage: x^61 '0' sage: y^61

[sage-devel] Permutation groups

2007-01-07 Thread David Kohel
Hi David J et al., There are two "natural" representations for permutations, cycles, and enumerated lists of images (or indices). In addition to this constructor: sage: G = SymmetricGroup(14) sage: G = SymmetricGroup(4) sage: g = G("(1,2,3,4)") sage: g(1) 2 sage: [ g(i+1) for i in range(4) ] [

[sage-devel] Re: Permutation groups

2007-01-08 Thread David Kohel
Hi William, Oops, I forgot to post my reply to my own message. This is the solution I found, using the same GAP manual entry for PermList. def gap_format_cycles(x): """ Put a permutation in Gap format, as a string. """ x = str(x).replace(' ','') return x.replace('),(',')(').repl

[sage-devel] Latex doctesting

2007-01-14 Thread David Kohel
It would be great if the latex preparsing with sage -t could also parse files included by \input{subfilename} --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PRO

[sage-devel] Permutation groups

2007-01-14 Thread David Kohel
sage: I = [3, 13, 16, 7, 15, 23, 6, 9, 10, 18, 5, 19, 24, 14, 25, 2, 11, 21, 4, 1, 12, 17, 8, 20, 22, 26] sage: G = SymmetricGroup(26) sage: G(I) I can't trace where the PermList string is getting lost on the way to or from the GAP interpreter, but here's a problem: sage: gap.eval('PermList(' +

[sage-devel] Euclidean div

2007-01-15 Thread David Kohel
For x, m != 0 in a Euclidean domain, one should have: x == m*(x.div(m)) + x.mod(m) Although one can get the result of x.div(m) as x.quo_rem(m)[0], but I would suggest having this as a separate function. I know that it is more efficient, if one wants both, to use quo_rem, and essentially no

[sage-devel] Dirty random

2007-01-15 Thread David Kohel
Any ideas how to get a random number from 1 to n in SAGE? Here's a bad way to do it: sage: n = 10^2 sage: G = SymmetricGroup(n) sage: G.random()(1) which will blow up as n goes to infinity. Here's a slightly better one: sage: x = random() sage: int(n*x) At least it gives a float's worth of

[sage-devel] Re: Dlogs

2007-01-23 Thread David Kohel
> I'm really glad I'm not writing everything in SAGE from scratch! Definitely. I can put this in this weekend, but if someone doesn't get to it sooner. --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe

[sage-devel] Re: Possible undergraduate projects

2007-01-23 Thread David Kohel
Hi Nils, Things that come to mind are: 1. LLL (wrapping existing code, not implementing it) and more canonical lattice reduction for small dimensions, with attention to what has been done in the context of quadratic forms? 2. Collaboration on robust p-adic arithmetic -- wrapping and/or testing

[sage-devel] Re: p-adics

2007-01-25 Thread David Kohel
Hi, The mploc might require further development to be stable in odd characteristics, but at least aims to be a standard p-adic C library. I am very interested in seeing p-adics developed, so please CC me: David R. Kohel <[EMAIL PROTECTED]> and my student: Hamish Law <[EMAIL PROTECTED]> with

[sage-devel] Re: integer.valuation and polynomial.valuation

2007-01-26 Thread David Kohel
Hi William, In agreement with Nils, f.valuation() should agree with -f.degree(). This should be a valid sage session: sage: f = x^3 + x^5 # = t^-3 + t^-5 = t^-5 (t^2 + 1) where t = 1/x sage: f.valuation() # should be the valuation at infinity with uniformizing parameter t -5 sage: f.factor() (x^

[sage-devel] Re: First remarks on new padics model

2007-03-07 Thread David Kohel
Hi, Another feature that I find extremely useful are the quotient rings (currently not implemented). This allows one to work in a well-defined ring, and control precision precisely. --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@go

[sage-devel] Re: Group Algebras in GAP/SAGE

2007-03-19 Thread David Kohel
Group algebras would be natural and interesting. I would suggest that they derive from FreeAlgebra, and improve those if the performance was inadequate. This gives a sparse representation, and as I remember, for finite dimensional (quotient) algebras, I use the explicit matrix representation on

[sage-devel] Re: Discrete log problem

2007-03-24 Thread David Kohel
(Partial) factorization (by trial division) of p-1 is in other to make use of CRT of discrete logarithms mod m where m | p-1. The index calculus algorithm requires a relations collection phase, and a linear algebra phase. The linear algebra phase just requires sparse linear algebra over F_2 to d

[sage-devel] Re: Discrete log problem

2007-03-25 Thread David Kohel
> To David Kohel: index calculus for discrete logs uses linear algebra mod p-1 > (not 2). Yes, I overstated the similarities between factorization and dlogs. --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.

[sage-devel] Re: Crypto package additions?

2007-05-29 Thread David Kohel
Hi Everyone, The main crypto functionality that I implemented concerns classical cryptography, for the purposes of teaching: http://echidna.maths.usyd.edu.au/~kohel/tch/Crypto/ Hence most of the systems are breakable (using suitable classical cryptanalytic attacks). The cryptosystem class can

[sage-devel] symbolic variables

2007-06-07 Thread David Kohel
I suggest that this automatic construction is too permissive: sage: x x sage: type(x) whereas this gives a perfectly reasonable compromise: sage: x = var('x') sage: x x sage: type(x) I realize that one wants to strike a balance between ease of use and the benefits of explicit typing in defin

[sage-devel] Re: symbolic variables

2007-06-07 Thread David Kohel
OK, William's response clarifies things, and I would just modify my comment to suggest that predefining any single character variable is questionable. I see that ALL upper and lower case alphabetic characters are so defined. I was thrown off by the definition of R (a ring to me), and am glad to

[sage-devel] Re: ticket #59 (optimize elliptic curve arithmetic)

2007-08-23 Thread David Kohel
I think the problem needs to be profiled. The problem is likely NOT in elliptic curves, but some horrendous chain of calls to module operations before getting to the (same) actual algorithms. Note that P*2 is slightly faster since it calls directly the member function of P rather than a function

[sage-devel] Re: Why Sage needs var(...) commands unlike Mathematica?

2008-11-03 Thread David Kohel
Hi John, To give a bit more weight to the counterargument against the alphabetti solution: > I agree, and I did not really mean my alphabetti suggestion to be > taken too seriously. In some version, there was an invasive declaration of single character symbols to be symbolic elements. This ca

[sage-devel] Re: Categories for the working programmer

2008-11-11 Thread David Kohel
Hi, I should point out that the class hierarchy should not be confused with the categories. The latter are intended to model the mathematics. In particular a homomorphism in the category of rings should satisfy f(x*y) = f(x)*f(y). Each class is assigned a default category, but the idea is that

[sage-devel] Re: Expected value of probability space

2008-12-01 Thread David Kohel
Hi Paul, > Thanks for explaining that, I see how that causes problems when S is not a > set of numbers. Even so, would it make sense for the random variable ps to > be the identity function X(x) = x on the probability space ps? Currently the > random variable ps is the function X(x) = P(x). Is th

[sage-devel] Re: Cardinality of a set...

2009-02-26 Thread David Kohel
Hi, Despite the length, I prefer cardinality() since card() is vague and obscure (and len(), size(), and count() ambiguous). I would argue that cardinality(), as distinct from len(), should consistently return a Sage Integer (or some concept of cardinal number) rather than a Python int. sage:

[sage-devel] Re: Double transpose on right_kernel()

2009-02-26 Thread David Kohel
Hi, As I have been creditted by William with the free modules as row vectors and default left kernel for matrices (under the influence of Magma), let me propose a coherent way to relax this design decision. It should be easy to add an argument to free modules to create them as column spaces and

[sage-devel] Re: Idea solicitation for semester-long algebra project

2009-03-01 Thread David Kohel
Implementing Florian Hess' article in Sage would be vey welcome, and I'm sure that Florian (or I for that matter) would be happy to given input. --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this

[sage-devel] Re: Naming convention again...

2009-03-01 Thread David Kohel
Hi, > I know nothing of combinatorics, but shouldn't accessing a set's n-th > element be more understandable using S[n] ? I agree. I would think S.index(x) would be more intuitive to a non- combinatorist like me. Do I understand correctly that these are sets enumerated by an indexing set (e.g.

[sage-devel] A magma evaluation and a parser bug

2009-03-04 Thread David Kohel
Hi, 1. Here is a bug in evaluation of Magma code sage: m = Magma() sage: s = "for i in [1..7] do print i^2+i+1; end for;" sage: m(s) ... TypeError: Error evaluating Magma code. IN:_sage_[5]:=for i in [1..7] do print i^2+i+1; end for; OUT: >> _sage_[5]:=for i in [1..7] do print i^2+i+1; end for;

[sage-devel] Re: Naming convention again...

2009-03-04 Thread David Kohel
Hi Florent, > > I would also like to see a class which is generally useful > > throughout Sage, as the default return type for many different > > finite or enumerable structures. > > I'm sorry but I don't understand what you mean by this sentence. Can you give > an example, please ? Jason Bandlo

[sage-devel] Enumerative structures in Sage

2009-03-04 Thread David Kohel
Hi, In Python (hence Sage) there exist simple aggregate or enumerative structures: dictionaries, lists (and tuples), and sets. Beyond these types, there are Sage Sequences and Sets, and (name under discussion) EnumeratedSets coming from the combinatorial community. For comparison, in Magma one h

[sage-devel] Re: A magma evaluation and a parser bug

2009-03-04 Thread David Kohel
Hi William, > Is all the code you have above GPL-licensed now? Yes, see: http://echidna.maths.usyd.edu.au/kohel/alg/index.html I need to update the code, but I propose that this could be an optional Sage package, for Magma users. This would ensure more users, and enforce testing against rot,

[sage-devel] Re: Sage 3.4.rc0

2009-03-05 Thread David Kohel
Build falled in clisp on MacOSX Leopard: cp -p cfgunix.lisp config.lisp chmod +w config.lisp echo '(setq *clhs-root-default* "http://www.lisp.org/HyperSpec/";)' >> config.lisp To continue building CLISP, the following commands are recommended (cf. unix/INSTALL step 4 ff): cd src emacs

[sage-devel] Re: Sage 3.4.rc0

2009-03-05 Thread David Kohel
Compilation got past clisp once I installed XCode 3.1.2. The lines before the above this reported that readline was too old, but I don't know if this was the source of the compile failure. --David --~--~-~--~~~---~--~~ To post to this group, send email to sage-de

[sage-devel] Re: Fwd: [MPFR] new license for GNU MPFR

2009-03-06 Thread David Kohel
Hi, The GPL3 decision will undoubtably be (continually) revisited, but the GPL3 license itself does not (yet) have the concensus of the open source community. Currently Microsoft Research is friendly to us, which I distinguish from Microsoft. Clearly MR is bound by Microsoft, whereas Sage is no

[sage-devel] Re: Riemann-Roch spaces in Magma

2009-03-09 Thread David Kohel
Can I suggest moving this discussion to sage-nt? Cheers, David --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit thi

[sage-devel] Re: Fractions with factored denominators

2009-03-12 Thread David Kohel
Hi, First, I think (at least last time I tried) there is a lot of room to speed up arithmetic in function fields, which would be my first priority. Second, as a mathematical construction, I think that the localizations A_S where A is a ring (e.g. UFD or PID) and S = {p_1,...,p_n} is a set of pri

[sage-devel] Re: Algebras with several bases, aka abstract parents with several concrete representations

2009-03-13 Thread David Kohel
Hi Nicolas, I would suggest that the choice of basis (or generators) should be an intrinsic part of the algebra's representation and interface. Different representations imply different (but possibly equal, even canonically equal) algebras. Compare free modules and polynomial rings: sage: V = F

[sage-devel] Power series rings

2009-03-13 Thread David Kohel
Hi, I am finding problems, holes, or missing features in power series rings and Laurent series rings. sage: K. = LaurentSeriesRing(QQ) sage: R. = PowerSeriesRing(QQ) 1. exp(t) is defined but exp(u) is not. 2. log(1 - t) and log(1-u) -- I started filling in this gap (below) for Laurent seri

[sage-devel] Re: hyperelliptic curve constructor question

2009-03-17 Thread David Kohel
Hi, We can move this over the sage-nt, but let me reply here. One improvement should be to, in fact, follow what John [Cremona)] did for elliptic curves -- replace points-as-morphisms with points as simple coordinates. In analogy with matrices and homomorphisms, for reasons of efficiency (and

[sage-devel] Re: p-adic precision loss in charpoly

2009-03-19 Thread David Kohel
Hi, The algorithm used doesn't need to be specific to the p-adics, but shouldn't apply an algorithm for fields or integral domains. Rather than the matrix code, it looks like this is the source of the problem: sage: M.parent().base_ring() 101-adic Ring with capped relative precision 2 sage: R.i

[sage-devel] Re: p-adic precision loss in charpoly

2009-03-19 Thread David Kohel
Hi, One can always work around a problem, but it would be better to discuss the best approach and put this in place. A related problem I had recently was in finding a random element of GL_n(ZZ/26ZZ) where n was 20-30. It was failing to terminate in the determinant computation. My guess is that

[sage-devel] Re: p-adic precision loss in charpoly

2009-03-20 Thread David Kohel
William, Thanks for pointing out that I was wrong about the lifting problem and original of this slow behavior. Rather than just putting in place the solution by lifting to ZZ, which you show to be much faster for reasonable size, I hope someone can profile arithmetic or linear algebra for ZZ/nZ

[sage-devel] Re: zero-dimensional schemes and multivariate polynomials in zero variables

2008-03-24 Thread David Kohel
Hi Martin et al., Magma doesn't support rank zero polynomial rings and this is a real pain when we were trying to implement schemes. I could give you examples which break the schemes code, but I made no progress in convincing Allan Steel to support this boundary case. On the other hand if the

[sage-devel] WIMS

2008-04-02 Thread David Kohel
I learned of WIMS (http://wims.unice.fr/) by virtue of the announcement of a new lecturer position here in Luminy, who is supposed to be responsible for computer-based teaching with WIMS (http://wims.unice.fr/). It overlaps many of the teaching- related goals of sage. I just downloaded it and ha

[sage-devel] Re: Cell splitting/merging in notebook

2008-04-02 Thread David Kohel
Hi, On the subject of notebook features: One feature that would be really nice is to have distinct text cells, in html or even better latex mode. A text cell could created by a hot key (say ) in edit mode which displays the source latex or html, then toggled out of edit mode to display the form

[sage-devel] Re: A Sage Enhancement Proposal: Lattice Modules

2008-04-28 Thread David Kohel
I support John's view that real-valued lattice need also to be taken into account. Minkowski lattices of number fields and Mordell-Weil groups are prime examples. Some people also like to embed lattices in R^n equipped with the standard Euclidean inner product. As such the coordinates are non-r

[sage-devel] Re: Fwd: Tensor products

2008-05-04 Thread David Kohel
Hi, Tensor products (of commutative rings) are "necessary" for representing the coordinate rings of a product of [affine] schemes. For commutative rings, a new tensor product class imay not be needed or desirable, rather what is missing currently is the homomorphisms. Given algebras A and B, I

[sage-devel] Re: Fwd: Tensor products

2008-05-07 Thread David Kohel
Hi, > > Given algebras A and B, I would return C and the two maps m1: A -> C > > and m2: B -> C: > > > (C, m1, m2) = A.tensor_product(B,ring=R) > > I might prefer to have something like > > C = A.tensor_product(B, ring=R) > > and then one can do > > C.coerce_map_from(A) > C.coerce_

[sage-devel] Re: Adding functions to Sage

2008-05-28 Thread David Kohel
Hi David, Nick, et al., I will also be arriving for SAGE Devel Days, on the 12th (with jetlag). I am interested on focusing on p-adic arithmetic and related constructions. A GaloisRing class is essentially an finite quotient of an unramified p-adic local ring; if a separate class is created, it

[sage-devel] Re: parent of component of CartesianProduct

2008-06-05 Thread David Kohel
Note that the intent of these SAGE constructors is not (just) to replicate the design (and errors) of Magma or other languages. There are natural product and coproduct constructions in various mathematical categories (e.g. a coproduct in Sets _is_ the union). The constructor CartesianProduct sho

[sage-devel] Re: sagemath.org relaunch

2008-07-11 Thread David Kohel
Hi Harald, Note that all of the mirrors, mine included in Sydney, rynchronize sage.math.washington.edu, so this site needs to be current. At present the line: Sage Devel Days 1 (aka Sage Days 8.5) will be in Seattle June 13-20, 2008 is out of date (and it lagged behind sagemath.org in announci

[sage-devel] Re: "page not found" for Kohel's cryptography notes

2008-08-28 Thread David Kohel
Hi Minh, David, et al., Feel free to link or copy these notes. My "old" address in Sydney should remain valid for at least the next 2 years, as I have an official honorary position there, but the notes may change, so a link would probably be preferable. Eventually I will to mirror my web page (a

[sage-devel] Re: SD10 Accomodation Again

2008-09-18 Thread David Kohel
Hi, Cc: Paul for comment on local information. This (http://www.hotel-eclipse.fr) looks inexpensive but (unless I'm mistaken), not accessible to LORIA or the center except by car. The center is reasonably accessible by tram; those working late at LORIA (if this is compatible with building securi

[sage-devel] Re: Sage 3.1.3.alpha3 released

2008-10-08 Thread David Kohel
Hi, I'm just trying to update my sage for SAGE Days 10, but find that the compilation hangs here: checking for paperconf... false checking for java... /usr/bin/java checking for javac... /usr/bin/javac checking for javah... /usr/bin/javah checking for jar... /usr/bin/jar checking whether Java co

[sage-devel] Re: Sage 3.1.3.alpha3 released

2008-10-08 Thread David Kohel
P.S. I get the same behavior for 3.1.2. --~--~-~--~~~---~--~~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-

[sage-devel] Re: accessors for FreeAlgebraElement

2009-05-13 Thread David Kohel
Hi Florent, I think the polynomial ring model should translate well to the non-commutative free algebras. In addition to access, specifying a (non-commutative) monomial ordering would be desirable. Generalizing these orderings is the only challenge in the generalization from free commutative al

[sage-devel] Re: verifying visual look of ReST in docstrings

2009-08-24 Thread David Kohel
Hi William, Thanks (to John Palmieri et al), such a feature was requested at Sage Days 16. Is there an interface in the command-line version or a command-line call on a file that doesn't request require starting up Sage? Cheers, David --~--~-~--~~~---~--~~ To p

[sage-devel] Re: verifying visual look of ReST in docstrings

2009-08-24 Thread David Kohel
I would prefer to generate a html or pdf file that I could view with standard tools or just read as plain text. Or maybe break the task into steps: extract the doc strings to a ReST file, and browse the ReST file with some "standard tools" (say rst2html file | lynx). The first step is important

[sage-devel] Re: EllipticCurveIsogeny: problems with entering a kernel polynomial to "E.isogeny(kernel)

2009-09-09 Thread David Kohel
Hi Jenny, Since the base ring of E is QQ, what do you expect to get for an input polynomial over Qt? A "feature" of Sage over, say, Magma, is that the the tracebacks are long (allowing debugging). Perhaps your entirely valid criticism is that the error in "+" is too late: some checking that th

[sage-devel] Re: Category review: what's the category of a category?

2009-10-21 Thread David Kohel
What about the category of categories (with functors as morphisms)? --David --~--~-~--~~~---~--~~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more

[sage-devel] Re: Categories review: algebra_modules.py, monoid_algebras.py and groupoids.py

2009-10-26 Thread David Kohel
Hi Nicolas, If I understand what existed and what is proposed, then I vote for the category Groupoids() and no arguments. A standard definition of a groupoid in category theory is a category in which every morphism is an isomorphism. Thus it is possible that this was intended as a constructor fo

[sage-devel] Re: Categories review: the last ones?

2009-10-29 Thread David Kohel
Hi, Glad to hear that Javier took up the last category files. I don't have a strong opinion whether OrderedSets (or Monoids) should have total or partial ordering. However, since there is a possible ambiguity, my preference is to not use OrderedX as an alias for either PartiallyOrderedX or Total

[sage-devel] Re: sage-4.2

2009-11-02 Thread David Kohel
Hi, What is the current status of MacOS 10.6 compatibility? I just downloaded sage-4.2.tar to my desktop machine and compilation fails in the singular package (see below). I don't seem to have succeeded in compiling sage-4.1.2 on any MacOS 10.6 desktop although it seems to have compiled on my 10.

[sage-devel] Re: sage-4.2

2009-11-03 Thread David Kohel
I've verified that I can build sage-4.2 on my laptop running 10.6, but that singular fails (with similar errors reported in the above logfile) on two recent Mac desktop machines with the latest XCode. A pending software update to 10.6.1 (requires a reboot) could explain the difference, but the sp

[sage-devel] Re: sage-4.2

2009-11-03 Thread David Kohel
Hi, I just verified that my home Mac desktop is 10.6.1 (and current for all Mac updates). I need to kill all of my jobs to update my office machine, so I deferred this step at work. However this is not the source of the problem. Instead it seems that the problem is due to running MacOSX in 64

[sage-devel] Re: InfinitePolynomialRing is -- very -- slow

2009-11-26 Thread David Kohel
Rather I would say that "sparse" should be the default: P. = InfinitePolynomialRing(QQ, implementation="sparse") Moreover, this syntax (and for gens, etc.) is inconsistent with PolynomialRing. The syntax: PolynomialRing(ring, integer, sparse=True) would be a more coherent, where integer=Set(ZZ

[sage-devel] Re: [sage-algebra] Re: Lattice, RealLattice, ComplexLattice, VectorSpaceLattice: a bikeshed question

2014-04-04 Thread David Kohel
Dear all, First of all, in the context of modules there should be no confusion about the terminology "lattice" (as opposed to a lattice poset in combinatorics). There is little doubt that modules with bilinear pairings are ubiquitous in mathematics, but precisely that poses problems with differin

Re: [sage-devel] Re: [sage-algebra] Re: Lattice, RealLattice, ComplexLattice, VectorSpaceLattice: a bikeshed question

2014-04-04 Thread David Kohel
Hi Martin, > I asked about it because it seems no one seems to have touched those data > structures in years and because I failed to interact with it the way I > wanted. > In my world I think of a lattice as given by a basis and my bases are over > the > integers. I failed to construct tha

Re: [sage-devel] Re: [sage-algebra] Re: Lattice, RealLattice, ComplexLattice, VectorSpaceLattice: a bikeshed question

2014-04-04 Thread David Kohel
On Friday, April 4, 2014 12:36:02 PM UTC+2, Volker Braun wrote: > > On Friday, April 4, 2014 11:19:11 AM UTC+1, Martin Albrecht wrote: >> >> existing one. However, in my case it would seem natural to improve the >> basis >> during the lifetime of an object. > > > IMHO that is always going to ca

[sage-devel] Re: SAGE in abstract algebra class

2010-03-12 Thread David Kohel
Hi Nicolas, The list sage-nt was set up to have a lower volume and lower noise forum for sage-devel issues with mathematical (number theoretic) interest. I also don't track sage-combinat for similar reasons as John, and miss most of what passes on sage-devel due to the high volume. Maybe there

[sage-devel] Re: Latest Magma fails to load

2010-03-19 Thread David Kohel
Hi, I solved this problem by changing the Magma script to not search in the DYLD_LIBRARY_PATH (in $ROOT/magma): #DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:$ROOT # original line DYLD_LIBRARY_PATH=$ROOT # hard code to use libgmp.3.dylib in $ROOT Similarly, if you want to use another libgmp3 (ve

[sage-devel] Re: mathematically correct eigen* methods of matrices.

2010-06-14 Thread David Kohel
Hi, Backwards compatibility or not, I consider this either a bad design or a bug: sage: M = Matrix([[1,-1],[1,0]]) sage: f = M.minimal_polynomial() sage: f.roots() [] sage: M.eigenvalues() [0.5? - 0.866025403784439?*I, 0.5? + 0.866025403784439?*I] First of all, wh

[sage-devel] Re: questions about sage/databases/*

2010-06-21 Thread David Kohel
Hi, > > 1. It seems to me that kohel.py is broken and has not been used in the > > past 5 years or so. > > Then I suppose we should remove it, unless David Kohel has objections. Go ahead and remove it. Cheers, David -- To post to this group, send an email to sage-devel@g

[sage-devel] Re: Coefficients of univariate polynomials

2011-05-12 Thread David Kohel
> On Tue, May 10, 2011 at 10:37 PM, Mike Hansen wrote: > > On Tue, May 10, 2011 at 6:52 PM, Rob Beezer wrote: > >> OK, thanks for the explanation, Tom.  p.exponents() was the missing > >> piece I did not have. > > > It would probably make sense to have p.monomials() method to be > > consistent wi

[sage-devel] Re: Deleting depreciated is_functions

2012-03-28 Thread David Kohel
Hi, 1. (On Sage syntax): For the record, there are some reasons why ZZ in Fields doesn't (and perhaps shouldn't) make sense: Fields is a function not the category it returns: sage: Fields sage: Fields() Category of fields I think a student learning Sage should have a first session in which the

[sage-devel] Re: categories and element classes

2012-03-28 Thread David Kohel
Hi Alex, This is a historical legacy of a heavy-handed attempt by William and me to implement schemes "from the book" (aka Hartshorne): sage: A = AffineSpace(2, ZZ) sage: p = A(0, 0) sage: p.parent().category().element_class sage: type(p) It is mathematically correct to say that a point is a s

[sage-devel] Re: All known bugs in Sage silently producing wrong answers

2012-03-28 Thread David Kohel
Hi, Here's one: sage: K. = NumberField(x-2/3) sage: K.is_prime_field() False The code is just a bit too naive: Source: def is_prime_field(self): r""" Return True if this ring is one of the prime fields `\QQ` or ` \GF{p}`. ... """ return False i.e. i

[sage-devel] Re: Poll: Making sage-mode a standard package

2012-05-30 Thread David Kohel
[X ] Make it standard at some point in the "near" future. Argument: Sage includes many interfaces to standard software. This includes software that the majority users will never use in their lifetimes, e.g. the big M's (unless at a mathematics department or institute where there exists a license)

[sage-devel] Re: projective space over rings and rational maps

2012-06-16 Thread David Kohel
Hi, Let me just comment on two related issues: 1. Rational maps are indeed interesting in geometry and the question of whether a given rational map is (i.e. extends to) a morphism is a hard question. In some situations one might want to consider two categories. For instance, do you assert that

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