Search results for " fat points"

showing 4 items of 4 documents

A conjecture on special linear systems of $mathbb{P}^3$

2005

Linear systems fat pointsSettore MAT/03 - Geometria
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Standard classes on the blow-up of $\mathbb{P}^n$ at points in very general position

2012

Linear systems fat points birational transformationsSettore MAT/03 - Geometria
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Elementary (-1)-curves of P-3

2006

In this note we deal with rational curves in P^3 which are images of a line by means of a finite sequence of cubo-cubic Cremona transformations. We prove that these curves can always be obtained applying to the line a sequence of such transformations increasing at each step the degree of the curve. As a corollary we get a result about curves that can give speciality for linear systems of P^3.

Discrete mathematicsSequenceAlgebra and Number TheoryDegree (graph theory)Linear system14C20Finite sequenceMathematics - Algebraic GeometryCorollaryLinear systems fat pointsFamily of curvesLine (geometry)FOS: MathematicsSettore MAT/03 - GeometriaAlgebraic Geometry (math.AG)Computer Science::DatabasesMathematics
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On multiples of divisors associated to Veronese embeddings with defective secant variety

2009

In this note we consider multiples aD, where D is a divisor of the blow-up of P^n along points in general position which appears in the Alexander and Hirschowitz list of Veronese embeddings having defective secant varieties. In particular we show that there is such a D with h^1(X,D) > 0 and h^1(X,2D) = 0.

DivisorGeneral MathematicsLinear systemLinear systems14C20CombinatoricsMathematics - Algebraic GeometrySecant varietyLinear systems fat pointsFOS: MathematicsSettore MAT/03 - Geometriafat pointsAlgebraic Geometry (math.AG)General positionMultipleMathematics
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