Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field

Let V ⊂ double-struck Pn(double-struck F¯q) be a complete intersection defined over a finite field double-struck Fq of dimension r and singular locus of dimension at most s, and let π :V → double-struck Ps+1 (double-struck F¯q) be a generic linear mapping. We obtain an effective version of the Berti...

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Publicado: 2015
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10715797_v31_n_p42_Cafure
http://hdl.handle.net/20.500.12110/paper_10715797_v31_n_p42_Cafure
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spelling paper:paper_10715797_v31_n_p42_Cafure2023-06-08T16:04:45Z Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field Bertini smoothness theorem Deligne estimate Hooley-Katz estimate Multihomogeneous Bézout theorem Polar varieties Rational points Singular locus Varieties over finite fields Bertini Deligne estimate Finite fields Hooley-Katz estimate Polar varieties Rational points Singular locus Let V ⊂ double-struck Pn(double-struck F¯q) be a complete intersection defined over a finite field double-struck Fq of dimension r and singular locus of dimension at most s, and let π :V → double-struck Ps+1 (double-struck F¯q) be a generic linear mapping. We obtain an effective version of the Bertini smoothness theorem concerning π, namely an explicit upper bound of the degree of a proper Zariski closed subset of double-struck Ps+1(double-struck F¯q) which contains all the points defining singular fibers of π. For this purpose we make use of the concept of polar variety associated with the set of exceptional points of π. As a consequence, we obtain results of existence of smooth rational points of V, that is, conditions on q which imply that V has a smooth double-struck Fq-rational point. Finally, for s = r - 2 and s = r - 3 we estimate the number of double-struck Fq-rational points and smooth double-struck Fq-rational points of V. © 2014 Elsevier Inc. All rights reserved. 2015 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10715797_v31_n_p42_Cafure http://hdl.handle.net/20.500.12110/paper_10715797_v31_n_p42_Cafure
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Bertini smoothness theorem
Deligne estimate
Hooley-Katz estimate
Multihomogeneous Bézout theorem
Polar varieties
Rational points
Singular locus
Varieties over finite fields
Bertini
Deligne estimate
Finite fields
Hooley-Katz estimate
Polar varieties
Rational points
Singular locus
spellingShingle Bertini smoothness theorem
Deligne estimate
Hooley-Katz estimate
Multihomogeneous Bézout theorem
Polar varieties
Rational points
Singular locus
Varieties over finite fields
Bertini
Deligne estimate
Finite fields
Hooley-Katz estimate
Polar varieties
Rational points
Singular locus
Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
topic_facet Bertini smoothness theorem
Deligne estimate
Hooley-Katz estimate
Multihomogeneous Bézout theorem
Polar varieties
Rational points
Singular locus
Varieties over finite fields
Bertini
Deligne estimate
Finite fields
Hooley-Katz estimate
Polar varieties
Rational points
Singular locus
description Let V ⊂ double-struck Pn(double-struck F¯q) be a complete intersection defined over a finite field double-struck Fq of dimension r and singular locus of dimension at most s, and let π :V → double-struck Ps+1 (double-struck F¯q) be a generic linear mapping. We obtain an effective version of the Bertini smoothness theorem concerning π, namely an explicit upper bound of the degree of a proper Zariski closed subset of double-struck Ps+1(double-struck F¯q) which contains all the points defining singular fibers of π. For this purpose we make use of the concept of polar variety associated with the set of exceptional points of π. As a consequence, we obtain results of existence of smooth rational points of V, that is, conditions on q which imply that V has a smooth double-struck Fq-rational point. Finally, for s = r - 2 and s = r - 3 we estimate the number of double-struck Fq-rational points and smooth double-struck Fq-rational points of V. © 2014 Elsevier Inc. All rights reserved.
title Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
title_short Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
title_full Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
title_fullStr Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
title_full_unstemmed Polar varieties, Bertini's theorems and number of points of singular complete intersections over a finite field
title_sort polar varieties, bertini's theorems and number of points of singular complete intersections over a finite field
publishDate 2015
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10715797_v31_n_p42_Cafure
http://hdl.handle.net/20.500.12110/paper_10715797_v31_n_p42_Cafure
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