The Generic Isogeny Decomposition of the Prym Variety of a Cyclic Branched Covering

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Authors

  • Theodosis Alexandrou

External Research Organisations

  • University of Bonn
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Details

Original languageEnglish
Article number2
JournalGEOMETRIAE DEDICATA
Volume216
Issue number1
Publication statusPublished - 3 Jan 2022
Externally publishedYes

Abstract

Let f:S′⟶S be a cyclic branched covering of smooth projective surfaces over C whose branch locus Δ⊂S is a smooth ample divisor. Pick a very ample complete linear system |H| on S, such that the polarized surface (S,|H|) is not a scroll nor has rational hyperplane sections. For the general member [C]∈|H| consider the μn-equivariant isogeny decomposition of the Prym variety Prym(C′/C) of the induced covering f:C′=f−1(C)⟶C:
Prym(C′/C)∼∏d|n, d≠1Pd(C′/C).
We show that for the very general member [C]∈|H| the isogeny component Pd(C′/C) is μd-simple with Endμd(Pd(C′/C))≅Z[ζd]. In addition, for the non-ample case we reformulate the result by considering the identity component of the kernel of the map Pd(C′/C)⊂Jac(C′)⟶Alb(S′).

Keywords

    math.AG, Isogeny decomposition, Jacobian variety, Prym variety, Cyclic covering

ASJC Scopus subject areas

Cite this

The Generic Isogeny Decomposition of the Prym Variety of a Cyclic Branched Covering. / Alexandrou, Theodosis.
In: GEOMETRIAE DEDICATA, Vol. 216, No. 1, 2, 03.01.2022.

Research output: Contribution to journalArticleResearch

Alexandrou T. The Generic Isogeny Decomposition of the Prym Variety of a Cyclic Branched Covering. GEOMETRIAE DEDICATA. 2022 Jan 3;216(1):2. doi: 10.1007/s10711-021-00671-6
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