Irreducibility of Hurwitz spaces

dc.creatorKanev, Vassil
dc.date2005-09-07
dc.date.accessioned2026-07-07T05:23:00Z
dc.date.available2026-07-07T05:23:00Z
dc.descriptionGraber, Harris and Starr proved, when n >= 2d, the irreducibility of the Hurwitz space H^0_{d,n}(Y) which parametrizes degree d coverings of a smooth, projective curve Y of positive genus, simply branched in n points, with full monodromy group S_d (math.AG/0205056). We sharpen this result and prove that H^0_{d,n}(Y) is irreducible if n >= max{2,2d-4} and in the case of elliptic Y if n >= max{2,2d-6}. We extend the result to coverings simply branched in all but one point of the discriminant. Fixing the ramification multiplicities over the special point we prove that the corresponding Hurwitz space is irreducible if the number of simply branched points is >= 2d-2. We study also simply branched coverings with monodromy group different from S_d and when n is large enough determine the corresponding connected components of H_{d,n}(Y). Our results are based on explicit calculation of the braid moves associated with the standard generators of the n-strand braid group of Y.
dc.descriptionlatex2e, 34 pages, 5 figures
dc.identifierhttps://arxiv.org/abs/math/0509154
dc.identifierhttp://arxiv.org/abs/math/0509154
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/76279
dc.subjectAlgebraic Geometry
dc.subjectGroup Theory
dc.subject14H10(Primary); 14H30, 20F36(Secondary)
dc.titleIrreducibility of Hurwitz spaces
dc.typetext

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