Invariants of the singularities of secant varieties of curves

Fuente: arXiv
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Main Author: Brogan, Daniel
Format: Preprint
Published: 2024
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author Brogan, Daniel
author_facet Brogan, Daniel
contents Consider a smooth projective curve and a given embedding into projective space via a sufficiently positive line bundle. We can form the secant variety of $k$-planes through the curve. These are singular varieties, with each secant variety being singular along the last. We study invariants of the singularities for these varieties. In the case of an arbitrary curve, we compute the intersection cohomology in terms of the cohomology of the curve. We then turn our attention to rational normal curves. In this setting, we prove that all of the secant varieties are rational homology manifolds, meaning their singular cohomology satisfies Poincaré duality. We then compute the nearby and vanishing cycles for the largest nontrivial secant variety, which is a projective hypersurface.
format Preprint
id arxiv_https___arxiv_org_abs_2408_16736
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Invariants of the singularities of secant varieties of curves
Brogan, Daniel
Algebraic Geometry
14F06, 14F08, 14F43, 14F45
Consider a smooth projective curve and a given embedding into projective space via a sufficiently positive line bundle. We can form the secant variety of $k$-planes through the curve. These are singular varieties, with each secant variety being singular along the last. We study invariants of the singularities for these varieties. In the case of an arbitrary curve, we compute the intersection cohomology in terms of the cohomology of the curve. We then turn our attention to rational normal curves. In this setting, we prove that all of the secant varieties are rational homology manifolds, meaning their singular cohomology satisfies Poincaré duality. We then compute the nearby and vanishing cycles for the largest nontrivial secant variety, which is a projective hypersurface.
title Invariants of the singularities of secant varieties of curves
topic Algebraic Geometry
14F06, 14F08, 14F43, 14F45
url https://arxiv.org/abs/2408.16736