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trying to use PARI for L-functions of modular forms#42039

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fchapoton wants to merge 4 commits intosagemath:developfrom
fchapoton:pari_lfun_modform
Open

trying to use PARI for L-functions of modular forms#42039
fchapoton wants to merge 4 commits intosagemath:developfrom
fchapoton:pari_lfun_modform

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@fchapoton
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instead of the Dokchitser scripts

📝 Checklist

  • The title is concise and informative.
  • The description explains in detail what this PR is about.

@fchapoton
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There remains a problem when handling non-cuspidal forms. Help is welcome.

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github-actions Bot commented Apr 19, 2026

Documentation preview for this PR (built with commit 591023d; changes) is ready! 🎉
This preview will update shortly after each push to this PR.

@fchapoton
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@AurelPage pourquoi est-ce que la reconnaissance automatique des poles ne marche pas ? Je donne à Pari les coefficients de la serie d'Eisenstein E4, et le parametre pole=0. Je croyais que Pari pouvait alors s'occuper de trouver les poles et le developpement de la fonction L completee en le pole ?

@fchapoton
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@AurelPage
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The poles cannot be detected automatically. For L-functions where the dual is the complex conjugate, if you provide the location of the poles and they are simple then the residues can be computed automatically.

@fchapoton
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fchapoton commented Apr 21, 2026

Merci Aurel.

Donc ca viendrait du fait que j'ai pas déclaré astar = 0 ? ou bien astar = 1 ?

je comprends pas ce que ces deux sentinel-values signifient exactement. EDIT: ok, c'est dans la doc, désolé

The doc says :

Finally, if a = a*, we allow a shortcut to describe the frequent situation where L has at most simple pole, at s = k, with residue r a complex scalar: you may then input poles = r. This value r can be set to 0 if unknown and it will be computed.

@edgarcosta
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Seems okay to me.

@fchapoton
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so is this a positive review ?

@edgarcosta
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yup. sorry!

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3 participants