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Related papers: Generalized Nonvanishing Conjecture and Iitaka Con…

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We study Gushel-Mukai (GM) varieties of dimension 4 or 6 in characteristic $p$. Our main result is the Tate conjecture for all such varieties over finitely generated fields of characteristic $p\geq 5$. In the case of GM sixfolds, we follow…

Algebraic Geometry · Mathematics 2024-11-19 Lie Fu , Ben Moonen

We show that the non-vanishing conjecture implies the abundance conjecture when $\nu\leq 1$. We also prove the abundance conjecture in dimension $\leq 5$ when $\kappa\geq 0$ and $\nu\leq 1$ unconditionally.

Algebraic Geometry · Mathematics 2025-08-01 Jihao Liu , Zheng Xu

In 1989 Kalai stated the three conjectures A, B, C of increasing strength concerning face numbers of centrally symmetric convex polytopes. The weakest conjecture, A, became known as the ``$3^d$-conjecture''. It is well-known that the three…

Combinatorics · Mathematics 2012-12-27 Raman Sanyal , Axel Werner , Günter M. Ziegler

We give a survey on noncommutative main conjectures of Iwasawa theory in a geometric setting, i.e. for separated schemes of finite type over a finite field, as stated and proved by Burns and the author. We will also comment briefly on…

Number Theory · Mathematics 2012-05-15 Malte Witte

We use the equivariant $\mu$-bubbles technique to prove that for any compact manifold $M^n$ with non-empty boundary, $n\in\{3,5,6\}$, the Yamabe invariant of $M^n$ is positive if and only if the Yamabe invariant of $M^n\times S^1$ is…

Differential Geometry · Mathematics 2023-09-26 Tongrui Wang , Xuan Yao

We study the relationship between Iitaka fibrations and the conjecture on the existence of complements, assuming the good minimal model conjecture. In one direction, we show that the conjecture on the existence of complements implies the…

Algebraic Geometry · Mathematics 2023-01-13 Guodu Chen , Jingjun Han , Jihao Liu

We answer an open question concerning the boundedness of canonical fiber spaces in high dimensions and prove the following: for any set of integers $n\geq 3$, $0<d<n$ and $N>0$, there exists a nonsingular projective $n$-fold $X$ of general…

Algebraic Geometry · Mathematics 2017-05-04 Meng Chen , Zhi Jiang

We prove a Kawamata-Viehweg vanishing theorem on a normal compact Kahler space X: if L is a nef line bundle with numerical dimension at least equal to 2, then the q-th cohomology group of K_X+L vanishes for q at least equal to the dimension…

Algebraic Geometry · Mathematics 2007-05-23 Jean-Pierre Demailly , Thomas Peternell

Let X be a compact K\"ahler manifold whose universal covering is $\mathbb C^n$. A conjecture of Iitaka claims that X is a torus, up to finite \'etale cover. We prove this conjecture in various cases in dimension four. We also show that in…

Algebraic Geometry · Mathematics 2017-11-07 Andreas Höring , Thomas Peternell , Ivo Radloff

Let X be a smooth projective threefold, and let A be an ample line bundle such that $K_X+A$ is nef. We show that if $K_X$ or $-K_X$ is pseudoeffective, the adjoint bundle $K_X+A$ has global sections. We also give a very short proof of the…

Algebraic Geometry · Mathematics 2018-01-15 Amaël Broustet , Andreas Höring

In this paper, we study the descent of positivity of the canonical bundle along fiber spaces. As a consequence, we prove a conjecture of Schnell, establishing the equivalence between the Non-vanishing Conjecture and its generalized version…

Algebraic Geometry · Mathematics 2025-12-23 Yongpan Zou

We prove the following generalization of Severi's Theorem: Let $X$ be a fixed complex variety. Then there exist, up to birational equivalence, only finitely many complex varieties $Y$ of general type of dimension at most three which admit a…

alg-geom · Mathematics 2014-12-02 Gerd Dethloff

We study Fano manifolds $X$ admitting an unsplit dominating family of rational curves and we prove that the Generalized Mukai Conjecture holds if $X$ has pseudoindex $i_X = (\dim X)/3$ or dimension $\dim X=6$. We also show that this…

Algebraic Geometry · Mathematics 2011-12-25 Carla Novelli

We prove that Seshadri constants of some ample divisors are bigger than 1 on smooth threefolds whose anticanonical bundle is nef or on Fano varieties of small coindice. The main tools are (some known cases of) the Kawamata's effective…

Algebraic Geometry · Mathematics 2007-10-15 Amaël Broustet

By applying the Chen-Jiang decomposition, we prove that the non-vanishing conjecture holds for an lc pair \((X, \Delta)\), where \(X\) is an irregular variety, provided it holds for lower-dimensional varieties. In the second part, we extend…

Algebraic Geometry · Mathematics 2025-01-09 Houari Benammar Ammar

We show that the M-canonical map of an n-dimensional complex projective manifold X of Kodaira dimension two is birational to an Iitaka fibration for a computable positive integer M. M depends on the index b of a general fibre F of the…

Algebraic Geometry · Mathematics 2018-06-20 Eckart Viehweg , De-Qi Zhang

In our previous work, we introduced the Generalised Nonvanishing Conjecture, which generalises several central conjectures in algebraic geometry. In this paper, we derive some surprising nonvanishing results for pluricanonical bundles which…

Algebraic Geometry · Mathematics 2020-04-01 Vladimir Lazić , Thomas Peternell

We prove a positive mass theorem for $n$-dimensional asymptotically flat manifolds with a non-compact boundary if either $3\leq n\leq 7$ or if $n\geq 3$ and the manifold is spin. This settles, for this class of manifolds, a question posed…

Differential Geometry · Mathematics 2014-07-03 Sergio Almaraz , Ezequiel Barbosa , Levi Lopes de Lima

The Generalized Smale Conjecture asserts that if M is a closed 3-manifold with constant positive curvature, then the inclusion of the group of isometries into the group of diffeomorphisms is a homotopy equivalence. For the 3-sphere, this…

Geometric Topology · Mathematics 2007-05-23 Darryl McCullough , J. H. Rubinstein

Motivated by work of Zhang from the early `90s, Medvedev and Scanlon formulated the following conjecture. Let $K$ be an algebraically closed field of characteristic $0$ and let $X$ be a quasiprojective variety defined over $K$ endowed with…

Algebraic Geometry · Mathematics 2016-10-24 Jason P. Bell , Dragos Ghioca , Zinovy Reichstein , Matthew Satriano