On the Rationality of Certain Strata of the Lange Stratification of Stable Vector Bundles on Curves
Keyword(s):
Abstract Let 𝑋 be a smooth projective curve of genus 𝑔 ≥ 2 and 𝑆(𝑟, 𝑑) the moduli scheme of all rank 𝑟 stable vector bundles of degree 𝑑 on 𝑋. Fix an integer 𝑘 with 0 < 𝑘 < 𝑟. H. Lange introduced a natural stratification of 𝑆(𝑟, 𝑑) using the degree of a rank 𝑘 subbundle of any 𝐸 ∈ 𝑆(𝑟, 𝑑) with maximal degree. Every non-dense stratum, say 𝑊(𝑘, 𝑟 – 𝑘, 𝑎, 𝑑 – 𝑎), has in a natural way a fiber structure ℎ : 𝑊(𝑘, 𝑟 – 𝑘, 𝑎, 𝑑 – 𝑎) → Pic𝑎(𝑋) × Pic𝑏(𝑋) with ℎ dominant. Here we study the rationality or the unirationality of the generic fiber of ℎ.
2012 ◽
Vol 23
(08)
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pp. 1250085
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1999 ◽
Vol 129
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pp. 229-234
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2010 ◽
Vol 21
(11)
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pp. 1505-1529
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2001 ◽
Vol 33
(5)
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pp. 535-542
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2008 ◽
Vol 144
(3)
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pp. 721-733
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