๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

On a sharp bound for the regularity index of any set of fat points

โœ Scribed by Giuliana Fatabbi; Anna Lorenzini


Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
178 KB
Volume
161
Category
Article
ISSN
0022-4049

No coin nor oath required. For personal study only.

โœฆ Synopsis


We propose an upper bound for the regularity index of fat points of P n with no geometric conditions on the points. Whenever the conjecture is true, the bound is sharp. It is, in fact, reached when there are points with high multiplicities either on a line or on some rational curve. Besides giving an easy proof of the conjecture in P 2 , we prove it in P 3 , by using some preliminary results which hold, more generally, in P n .


๐Ÿ“œ SIMILAR VOLUMES


On Bounding the Number of Generators for
โœ Stephanie Fitchett ๐Ÿ“‚ Article ๐Ÿ“… 2001 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 145 KB

Let X be the surface obtained by blowing up general points p 1 p n of the projective plane over an algebraically closed ground field k, and let L be the pullback to X of a line on the plane. If C is a rational curve on X with C โ€ข L = d, then for every t there is a natural map C C t โŠ— X X L โ†’ C C t +

A sharp upper bound for the number of st
โœ Hongbo Hua ๐Ÿ“‚ Article ๐Ÿ“… 2009 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 648 KB

Let G be a connected and simple graph, and let i(G) denote the number of stable sets in G. In this letter, we have presented a sharp upper bound for the i(G)-value among the set of graphs with k cut edges for all possible values of k, and characterized the corresponding extremal graphs as well.