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A Cremona transformation of five-dimensional projective space is constructed. The degree of the transformation is 7. The inequalities of Fano are not fulfilled for this transformation.

Algebraic Geometry · Mathematics 2007-05-23 Marat Gizatullin

A birational transformation of three-dimensional quadric is constructed. The inequalities of fano are not fulfilled for this transformation.

Algebraic Geometry · Mathematics 2007-05-23 Marat Gizatullin

Two projective varieties are said to be Cremona equivalent if there is a Cremona modification sending one onto the other. In the last decade, Cremona equivalence has been investigated widely, and we now have a complete theory for…

Algebraic Geometry · Mathematics 2026-03-23 Massimiliano Mella

Extending some results of Crauder and Katz, and Ein and Shepherd-Barron on special Cremona transformations, we study birational transformations of the complex projective spaces onto prime Fano manifolds such that the base locus X of the…

Algebraic Geometry · Mathematics 2013-09-13 Alberto Alzati , José Carlos Sierra

We consider Cremona transformations of the complex projective space of dimension 3 which factorize as a product of at most two elementary links of type II, without small contractions, connecting two Fano 3-folds. We show that there are…

Algebraic Geometry · Mathematics 2013-09-23 Ivan Pan

We will show the rationality of the function field of two variables under certain Cremona transformation.

Algebraic Geometry · Mathematics 2007-09-11 Akinari Hoshi , Ming-chang Kang

In this technical note, we give two extensions of the classical Fano inequality in information theory. The first extends Fano's inequality to the setting of estimation, providing lower bounds on the probability that an estimator of a…

Information Theory · Computer Science 2014-01-03 John C. Duchi , Martin J. Wainwright

Two divisors in $\mathbb P^n$ are said to be Cremona equivalent if there is a Cremona modification sending one to the other. In this paper I study irreducible cones in $\mathbb P^n$ and prove that two cones are Cremona equivalent if their…

Algebraic Geometry · Mathematics 2014-07-31 Massimiliano Mella

This article studies the group generated by automorphisms of the projective space of dimension $n$ and by the standard birational involution of degree $n$. Every element of this group only contracts rational hypersurfaces, but in odd…

Algebraic Geometry · Mathematics 2019-02-14 Jérémy Blanc , Isac Hedén

In this note, we present an information diffusion inequality derived from an elementary argument, which gives rise to a very general Fano-type inequality. The latter unifies and generalizes the distance-based Fano inequality and the…

Information Theory · Computer Science 2015-04-22 Gábor Braun , Sebastian Pokutta

We identify a one-parameter family of inequalities for the Fourier transform whose limiting case is the restriction conjecture for the sphere. Using Stein's method of complex interpolation we prove the conjectured inequalities when the…

Analysis of PDEs · Mathematics 2023-06-06 Nicola Garofalo

We construct examples of Fano manifolds, which are defined over a field of positive characteristic, but not over $\com$.

Algebraic Geometry · Mathematics 2017-06-20 Ilya Karzhemanov

Two reduced projective schemes are said to be Cremona equivalent if there is a Cremona map that maps one in the other. In this paper I revise some of the known results about Cremona equivalence and extend the main result of [MP09] to…

Algebraic Geometry · Mathematics 2022-03-30 Massimiliano Mella

An analytical derivation of Fano line-shape asymmetry ratio has been presented here for a general case. It is shown that Fano line-shape becomes less asymmetric as \q is increased and finally becomes completely symmetric in the limiting…

Mesoscale and Nanoscale Physics · Physics 2014-03-26 Rajesh Kumar

We present a manifestly geometrically self-dual version of the Fano harmonicity axiom for the projective plane.

Combinatorics · Mathematics 2017-05-02 P. L. Robinson

We study the enumerativity of Gromov-Witten invariants where the domain curve is fixed in moduli and required to pass through the maximum possible number of points. We say a Fano manifold satisfies asymptotic enumerativity if such…

Algebraic Geometry · Mathematics 2024-12-04 Roya Beheshti , Brian Lehmann , Carl Lian , Eric Riedl , Jason Starr , Sho Tanimoto

We extend our classification of special Cremona transformations whose base locus has dimension at most three to the case when the target space is replaced by a (locally) factorial complete intersection.

Algebraic Geometry · Mathematics 2019-07-24 Giovanni Staglianò

Two divisors in $\P^n$ are said to be Cremona equivalent if there is a Cremona modification sending one to the other. We produce infinitely many non equivalent divisorial embeddings of any variety of dimension at most 14. Then we study the…

Algebraic Geometry · Mathematics 2011-03-25 Massimiliano Mella , Elena Polastri

This paper generalizes the first author's preceding works concerning admissible functions on certain Fano manifolds. Here, we study a larger class of functions which can be less symmetric than the ones studied before. When the sup of these…

Differential Geometry · Mathematics 2010-06-09 Adnene Ben Abdesselem , Brahim Dridi

The goal of this paper is to explore the genus and degree of the Fano scheme of linear subspaces on a complete intersection in a complex projective space. Firstly, suppose that the expected dimension of the Fano scheme is one, we prove a…

Algebraic Geometry · Mathematics 2017-01-03 Dang Tuan Hiep
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