[sage-support] modular symbols mod 3

Hi Everyone, I'm getting what I perceive to be an error when I compute some spaces of modular symbols mod 3. (Probably the same phenomenon occurs mod 2.) Specifically: sage: N=7*13 sage: for l in primes(20): ... ModularSymbols(Gamma0(N),2,base_ring=GF(l)).cuspidal_submodule().dimension(

[sage-support] standard deviations in sage

Hello All, I asked myself how I could use sage to compute the standard deviation of a grade distribution for one of my courses. Rooting around, I found that I can compute for example sage: vector(RDF,[1,2,2,1]).standard_deviation() and get the answer 0.57735026919. However, if I try the same

[sage-support] points on elliptic curves mod N

Hi, I'd like to present Lenstra's elliptic curve factoring method to a class. This means that I'd like to define an elliptic curve over Integers(N), where N is composite, and then add points on that curve in sage. I may be doing something stupid, but I'm getting a NotImplementedError with the

[sage-support] surprised by behavior of "torsion_subgroup"

Hi,Maybe this is a frivolous comment, but I'd like to express my surprise at the use of "torsion_subgroup" to mean two very different things for an abelian variety and for an elliptic curve:sage: E=EllipticCurve('11a')sage: E.torsion_subgroup()Torsion Subgroup isomorphic to Multiplicative Abelian G

[sage-support] gcd's of numbers mod N

Hi everyone, If a is an integer mod m (and m is a positive integer), then the gcd of a and m is well defined; it's the gcd of A and m were A is any integer representing a mod m. Consider this transcript in sage: sage: a = Mod(1,6) sage: b = Mod(3,6) sage: print gcd(a-b,6) # is this a bug? sage

[sage-support] elliptic curve extension degree

Consider this short sage transcript: sage: E=EllipticCurve(GF(3),[1,1]) sage: for i in range(3): ... print i,E.order(extension_degree=i) 0 4 1 4 2 16 Sage seem to think that E has 4 points over the field with 1 element. Was this intended? Ken -- To post to this group, send email to sag

[sage-support] strange behavior in sage 5.0

Any advice here? Am I doing something wrong: > sage: 1+1 > 2 > sage: (0.8*0.15)/(0.8*0.15 + 0.2*0.85) > > > Unhandled SIGILL: An illegal instruction occurred in Sage. > This probably occurred because a *compiled* component

[sage-support] weird comparison of rational numbers

Hi Sage Gurus, Am I doing something stupid here: sage: print 1/2 < 3/7 sage: L=[] sage: for i in range(2,3): ... for j in range(1,2): ... L.append([i,j]) ... sage: print L sage: for P in L: ... print P[1], P[0] ... P[1]/P[0] < 3/7 False [[2, 1]] 1 2 True In plai