On factoriality of nodal threefolds
Copyright policy )On factoriality of nodal threefolds
We prove the $\mathbb{Q}$-factoriality of a nodal hypersurface in $\mathbb{P}^{4}$ of degree $n$ with at most ${\frac{(n-1)^{2}}{4}}$ nodes and the $\mathbb{Q}$-factoriality of a double cover of $\mathbb{P}^{3}$ branched over a nodal surface of degree $2r$ with at most ${\frac{(2r-1)r}{3}}$ nodes.
28 pages, in the last version we change the introduction
- Steklov Mathematical Institute Russian Federation
- University of Edinburgh United Kingdom
- Department of Mathematical Sciences Russian Federation
Mathematics - Algebraic Geometry, 14J30, 14J17, 14J70, 14E07, 14E08, 14J45, Rationality questions in algebraic geometry, FOS: Mathematics, \(3\)-folds, linear system, Divisors, linear systems, invertible sheaves, double cover, Algebraic Geometry (math.AG), Singularities of surfaces or higher-dimensional varieties
Mathematics - Algebraic Geometry, 14J30, 14J17, 14J70, 14E07, 14E08, 14J45, Rationality questions in algebraic geometry, FOS: Mathematics, \(3\)-folds, linear system, Divisors, linear systems, invertible sheaves, double cover, Algebraic Geometry (math.AG), Singularities of surfaces or higher-dimensional varieties
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).21 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Average influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 10% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
Citations provided by BIP!Popularity provided by BIP!