Magma

MAGMA Computational Algebra System

Magma
 •  How to get it
 •  Download
 •  Online Demo
 
Resources
 •  Online Help
 •  Discovering Mathematics with Magma
 •  Citations
 •  How to cite Magma
 •  Links
 •  Contact us
 
[Next][Prev] [Right] [Left] [Up] [Index] [Root]

Heights

NaiveHeight(P) : PtEll -> FldPrElt
The naive x-coordinate height of a point P on an elliptic curve over a function field K, in other words, the degree of the point (x(P):1) on the projective line.
Height(P) : PtEll -> FldRatElt
The N{'e}ron-Tate height of the given point P on an elliptic curve defined over a function field.
LocalHeight(P, Pl) : PtEll, PlcFunElt -> FldPrElt
Given a point P on an elliptic curve defined over a function field F and a place Pl of the function field F, the function returns the local height λPl(P) at Pl of P.
HeightPairing(P, Q) : PtEll[FldFunG], PtEll[FldFunG] -> FldRatElt
Given points P and Q, the function computes the height pairing, defined as <P, Q> = (h(P + Q) - h(P) - h(Q))/2 where h denotes the N{'e}ron-Tate height.
HeightPairingMatrix(S) : SeqEnum[PtEll[FldFunG]] -> AlgMatElt
Given a sequence S of points Pi on an elliptic curve defined over a function field, this function returns the matrix (< Pi, Pj >), where < , > is the height pairing.
HeightPairingLattice(S) : [PtEll[FldFunG]] -> AlgMatElt, Map
The height pairing lattice of a sequence of independent points on an elliptic curve defined over a function field.
Basis(s) : [ PtEll ] -> [ PtEll ], ModMatAlgElt
Given a sequence s of points on an elliptic curve, returns a sequence of points that form a basis for the free part of the subgroup generated by the points in s. The second returned value is a Gram matrix for this basis with respect to the N'eron-Tate pairing.
Basis(seq,r,disc) : SeqEnum -> SeqEnum
Given a sequence seq of points on an elliptic curve, returns a sequence of independent points in the free part of the subgroup generated by the given points, which generate a lattice of rank r and discriminant disc. The answer is returned as soon as such a lattice has been found, ignoring any additional points in the given sequence.
IsLinearlyDependent(points) : [PtEll] -> BoolElt, ModTupRngElt
IsLinearlyIndependent(points) : [PtEll] -> BoolElt, ModTupRngElt
IndependentGenerators(points) : [PtEll] -> [PtEll]
These functions are available for elliptic curves over function fields, and behave the same way as for elliptic curves over the rationals.
 [Next][Prev] [Right] [Left] [Up] [Index] [Root]
                       

Version: V2.16 of Mon Nov 16 15:04:45 EST 2009

Valid HTML 4.01! Valid CSS!