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I know that for some L-series there is still a rapidly-converging series. My question is about the existence of a such a series for the Dirichlet series of the Hasse–Weil L-function associated with an elliptic curve over rationals. A google search do not gives important answers.

flag	asked Nov 20 at 16:30 RH 105●1●9

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Where do you want the series to converge rapidly? If it's the whole complex plane, such a series would be a proof of analytic continuation, which is as hard as modularity. Thus, you probably want to find the associated modular form and look for a rapidly converging series for the L-function of that modular form? – Will Sawin Nov 20 at 17:22

for any complex number s. I remamber that there is a rapidly converging series obtained by using Lavrik method, but I can't find it. – RH Nov 20 at 17:26

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Yes, there is a rapidly exponentially converging series for L(E,s) which relies on the functional equation and thus on modularity of E. This has been implemented, see e.g. arxiv.org/abs/math/0207280 If you're more interested in values of s with high imaginary part, then you might need other methods, like the double exponential method. See Pascal Molin's PhD thesis math.jussieu.fr/~molinp/files/these.pdf – François Brunault Nov 20 at 17:48

Thank you Francois. – RH Nov 20 at 18:01

Denis Chaperon de Lauzières · Accepted Answer · 2012-11-20 17:39:22Z UTC

Possibly the answer would be the so-called "approximate functional equation" for the $L$-function. This of course takes as input the modularity of the Hasse-Weil zeta function, and gives rapidly convergent series representing it at any point. I would expect Cremona's book on algorithms for modular elliptic curves to contain a description. Software like Pari/GP implements such algorithms (see the command elllseries).

A rapidly-converging series of the Hasse–Weil L-function associated with an elliptic curve over rationals

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