1,978 research outputs found
Pseudo-effective and numerically flat reflexive sheaves
In this note, we discuss the concept of pseudoeffective vector bundle and
also introduce pseudoeffective torsion-free sheaves over compact K\"ahler
manifolds. We show that a pseudoeffective reflexive sheaf over a compact
K\"ahler manifold with vanishing first Chern class is in fact a numerically
flat vector bundle. A proof is obtained through a natural construction of
positive currents representing the Segre classes of pseudoeffective vector
bundles.Comment: 45 pages, rewrite section 3 and section
Canonical duality approach in the approximation of optimal Monge mass transfer mapping
This paper mainly addresses the Monge mass transfer problem in the 1-D case.
Through an ingenious approximation mechanism, one transforms the Monge problem
into a sequence of minimization problems, which can be converted into a
sequence of nonlinear differential equations with constraints by variational
method. The existence and uniqueness of the solution for each equation can be
demonstrated by applying the canonical duality method. Moreover, the duality
method gives a sequence of perfect dual maximization problems. In the final
analysis, one constructs the approximation of optimal mapping for the Monge
problem according to the theoretical results.Comment: 15 pages, 0 figure. arXiv admin note: substantial text overlap with
arXiv:1607.0655
An approximation method for the optimization of -th moment of -valued random variable
This paper mainly addresses the optimization of -th moment of
-valued random variable. Through an ingenious approximation
mechanism, one transforms the maximization problem into a sequence of
minimization problems, which can be converted into a sequence of nonlinear
differential equations with constraints by variational approach. The existence
and uniqueness of the solution for each equation can be demonstrated by
applying the canonical duality method. Moreover, the dual transformation gives
a sequence of perfect dual maximization problems. In the final analysis, one
constructs the approximation of the probability density function accordingly.Comment: 11 pages, 0 figure. arXiv admin note: substantial text overlap with
arXiv:1607.0655
Control of Spin in La(Mn,Zn)AsO Alloy by Carrier Doping
The control of spin without magnetic field is one of challenges in developing
spintronic devices. In an attempt to solve this problem, we proposed a novel
hypothetic LaMn0.5Zn0.5AsO alloy from two experimentally synthesized rare earth
element transition metal arsenide oxides, i.e. LaMnAsO and LaZnAsO. On the
basis of the first-principles calculations with strong-correlated correction,
we found that the LaMn0.5Zn0.5AsO alloy is an antiferromagnetic semiconductor
at ground state, while bipolar magnetic semiconductor at ferromagnetic state.
Both electron and hole doping in the LaMn0.5Zn0.5AsO alloy induces the
transition from antiferromagnetic to ferromagnetic, as well as semiconductor to
half metal. In particular, the spin-polarization direction is switchable
depending on the doped carrier's type. As carrier doping can be realized easily
in experiment by applying a gate voltage, the LaMn0.5Zn0.5AsO alloy stands for
a promising spintronic material to generate and control the spin-polarized
carriers with electric field.Comment: 16 pages, 4 figure
A new multi-component CKP hierarchy
We construct a new multi-component CKP hierarchy based on the eigenfunction
symmetry reduction. It contains two types of CKP equation with self-consistent
sources which Lax representations are presented. Also it admits reductions to
-constrained CKP hierarchy and to a (1+1)-dimensional soliton hierarchy with
self-consistent source, which include two types of Kaup-Kuperschmidt equation
with self-consistent sources and of bi-directional Kaup-Kuperschmidt equation
with self-consistent sources.Comment: 8 page
Two new multi-component BKP hierarchies
We firstly propose two kinds of new multi-component BKP (mcBKP) hierarchy
based on the eigenfunction symmetry reduction and nonstandard reduction,
respectively. The first one contains two types of BKP equation with
self-consistent sources which Lax representations are presented. The two mcBKP
hierarchies both admit reductions to the constrained BKP hierarchy and to
integrable (1+1)-dimensional hierarchy with self-consistent sources, which
include two types of SK equation with self-consistent sources and of
bi-directional SK equations with self-consistent sources.Comment: 12 page
Pose Invariant 3D Face Reconstruction
3D face reconstruction is an important task in the field of computer vision.
Although 3D face reconstruction has being developing rapidly in recent years,
it is still a challenge for face reconstruction under large pose. That is
because much of the information about a face in a large pose will be
unknowable. In order to address this issue, this paper proposes a novel 3D face
reconstruction algorithm (PIFR) based on 3D Morphable Model (3DMM). After input
a single face image, it generates a frontal image by normalizing the image.
Then we set weighted sum of the 3D parameters of the two images. Our method
solves the problem of face reconstruction of a single image of a traditional
method in a large pose, works on arbitrary Pose and Expressions, greatly
improves the accuracy of reconstruction. Experiments on the challenging AFW,
LFPW and AFLW database show that our algorithm significantly improves the
accuracy of 3D face reconstruction even under extreme poses .Comment: 8 page
On the hard Lefschetz theorem for pseudoeffective line bundles
In this note, we obtain a number of results related to the hard Lefschetz
theorem for pseudoeffective line bundles, due to Demailly, Peternell and
Schneider. Our first result states that the holomorphic sections produced by
the theorem are in fact parallel, when viewed as currents with respect to the
singular Chern connection associated with the metric. Our proof is based on a
control of the covariant derivative in the approximation process used in the
construction of the section. Then we show that we have an isomorphsim between
such parallel sections and higher degree cohomology. As an application, we show
that the closedness of such sections induces a linear subspace structure on the
tangent bundle. Finally, we discuss some questions related to the optimality of
the hard Lefschetz theorem.Comment: 17 pages. arXiv admin note: substantial text overlap with
arXiv:1401.5432, arXiv:math/0006205 by other author
On a vanishing theorem due to Bogomolov
In this note, we give a new proof of a vanishing result originally due to
Bogomolov, and later generalised by Mourougane and Boucksom. The statement
holds for arbitrary pseudoeffective line bundles over compact K\"ahler
manifolds, under an assumption on the numerical dimension of the line bundle.Comment: 11 page
On the Nakano vanishing theorem
In this note, we state various generalisations of the Nakano vanishing
theorem under weak positivity assumptions, and compare them with the known
results.Comment: 5 page
- β¦