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We consider a smooth projective morphism between smooth complex projective varieties. If the source space is a weak Fano (or Fano) manifold, then so is the target space. Our proof is Hodge theoretic. We do not need mod $p$ reduction…

Algebraic Geometry · Mathematics 2010-05-03 Osamu Fujino , Yoshinori Gongyo

Fano mechanism is the universal explanation of asymmetric resonance appearing in different systems. We report the evidence of Fano-like resonance in selective reflection from a resonant two-level medium. We draw an analogy with the…

Optics · Physics 2016-04-13 Denis V. Novitsky

We describe an infinite set of smooth projective threefolds that have equivalent derived categories but are not isomorphic, contrary to a conjecture of Kawamata. These arise as blow-ups of $\mathbb P^3$ at various configurations of 8…

Algebraic Geometry · Mathematics 2013-11-04 John Lesieutre

We consider the problem to determine which blow-ups along subvarieties in products of two projective spaces are log Fano. By describing the nef cones of such blow-ups with special centers, we give a partial classification result. For each…

Algebraic Geometry · Mathematics 2018-09-25 Toru Tsukioka

This article studies the possible degenerations of plane Cremona transformations of some degree into maps of smaller degree.

Algebraic Geometry · Mathematics 2015-09-30 Jérémy Blanc , Alberto Calabri

We give a counterexample to a recently conjectured variant of the Penrose inequality.

Differential Geometry · Mathematics 2026-04-30 Sven Hirsch , Yipeng Wang

We give a simple proof of the non-rationality of the Fano threefold defined by the equations \Sigma x_i = \Sigma x_i^2 = \Sigma x_i^3 = 0 in P^6 .

Algebraic Geometry · Mathematics 2011-02-08 Arnaud Beauville

In this note we study Fano threefolds with noncyclic torsion in the divisor class group. Since they can all be obtained as quotients of Fano threefolds, we get also all examples that can be obtained as quotients of low codimension Fanos in…

Algebraic Geometry · Mathematics 2007-06-14 Jorge Caravantes

Answering an old question of M.Hata, we construct an example of a 1-dimensional Peano continuum which is not homeomorphic to an attractor of IFS.

General Topology · Mathematics 2014-12-04 Taras Banakh , Magdalena Nowak

We consider a transformation of a normalized measure space such that the image of any point is a finite set. We call such transformation $m$-transformation. In this case the orbit of any point looks like a tree. In the study of…

Dynamical Systems · Mathematics 2007-05-23 Konstantin Igudesman

It is demonstrated that, unless the meaning of conformal transformations for the underlying geometrical structure is discussed on a same footing as it is done for the equations of the given gravity theory, the notion of "conformal…

General Relativity and Quantum Cosmology · Physics 2011-08-18 Israel Quiros , Ricardo Garcia-Salcedo , Jose Edgar Madriz Aguilar

We extend Fano's inequality, which controls the average probability of events in terms of the average of some $f$--divergences, to work with arbitrary events (not necessarily forming a partition) and even with arbitrary $[0,1]$--valued…

Statistics Theory · Mathematics 2019-06-12 Sebastien Gerchinovitz , Pierre Ménard , Gilles Stoltz

In this note, we show that there is some counterexample for isoperimetric inequality if the condition $(\phi')^2-\phi"\phi\leq 1$ does not hold in warped product space.

Differential Geometry · Mathematics 2016-10-10 Li Chunhe , Wang Zhizhang

In this paper we investigate the degrees of irrationality of degenerations of $\epsilon$-lc Fano varieties of arbitrary dimensions. We show that given a generically $\epsilon$-lc klt Fano fibration $X\to Z$ of dimension $d$ over a smooth…

Algebraic Geometry · Mathematics 2026-04-03 Caucher Birkar , Santai Qu

A natural analogue of the Krein--Milman theorem is shown to fail for CAT(0) spaces.

Metric Geometry · Mathematics 2016-06-07 Nicolas Monod

We study norm inequalities for the Fourier transform, namely, \begin{equation}\label{introduction} \|\widehat f\|_{X_{p,q}^\lambda} \lesssim \|f\|_{Y}, \end{equation} where $X$ is either a Morrey or Campanato space and $Y$ is an appropriate…

Classical Analysis and ODEs · Mathematics 2023-10-25 Alberto Debernardi Pinos , Erlan Nursultanov , Sergey Tikhonov

We prove a central limit theorem for the algebraic and dynamical degrees of a random composition of Cremona transformations.

Dynamical Systems · Mathematics 2021-02-23 Nguyen-Bac Dang , Giulio Tiozzo

We examine a particular kind of six-dimensional Cremonian universe featuring one dimension of space, three dimensions of time and other two dimensions that can*not* be ranked as either time or space. One of these two, generated by a…

General Physics · Physics 2015-06-26 Metod Saniga

In this paper we present an effective method for linearizing rational varieties of codimension at least two under Cremona transformations, starting from a given parametrization. Using these linearizing Cremonas, we simplify the equations of…

Algebraic Geometry · Mathematics 2014-11-18 Ciro Ciliberto , Maria Angelica Cueto , Massimiliano Mella , Kristian Ranestad , Piotr Zwiernik

Two birational subvarieties of P^n are called Cremona equivalent if there is a Cremona modification of P^n mapping one to the other. If the codimension of the varieties is at least 2 then they are always Cremona Equivalent. For divisors the…

Algebraic Geometry · Mathematics 2020-07-30 Massimiliano Mella