705 research outputs found
On the Inverse Problem Relative to Dynamics of the w Function
In this paper we shall study the inverse problem relative to dynamics of the
w function which is a special arithmetic function and shall get some results.Comment: 11 page
On number fields with nontrivial subfields
What is the probability for a number field of composite degree to have a
nontrivial subfield? As the reader might expect the answer heavily depends on
the interpretation of probability. We show that if the fields are enumerated by
the smallest height of their generators the probability is zero, at least if
. This is in contrast to what one expects when the fields are enumerated
by the discriminant. The main result of this article is an estimate for the
number of algebraic numbers of degree and bounded height which generate
a field that contains an unspecified subfield of degree . If
we get the correct asymptotics as the height tends to
infinity
Lang's Conjecture and Sharp Height Estimates for the elliptic curves
For elliptic curves given by the equation , we
establish the best-possible version of Lang's conjecture on the lower bound of
the canonical height of non-torsion points along with best-possible upper and
lower bounds for the difference between the canonical and logarithmic height.Comment: published version. Lemmas 5.1 and 6.1 now precise (with resultant
refinement to Theorem 1.2). Small corrections to
Anomalous Subvarieties—Structure Theorems and Applications
When a fixed algebraic variety in a multiplicative group variety is intersected with the union of all algebraic subgroups of fixed dimension, a key role is played by what we call the anomalous subvarieties. These arise when the algebraic variety meets translates of subgroups in sets larger than expected. We prove a Structure Theorem for the anomalous subvarieties, and we give some applications, emphasizing in particular the case of codimension two. We also state some related conjectures about the boundedness of absolute height on such intersections as well as their finitenes
The theory of the exponential differential equations of semiabelian varieties
The complete first order theories of the exponential differential equations
of semiabelian varieties are given. It is shown that these theories also arises
from an amalgamation-with-predimension construction in the style of Hrushovski.
The theory includes necessary and sufficient conditions for a system of
equations to have a solution. The necessary condition generalizes Ax's
differential fields version of Schanuel's conjecture to semiabelian varieties.
There is a purely algebraic corollary, the "Weak CIT" for semiabelian
varieties, which concerns the intersections of algebraic subgroups with
algebraic varieties.Comment: 53 pages; v3: Substantial changes, including a completely new
introductio
Section Extension from Hyperbolic Geometry of Punctured Disk and Holomorphic Family of Flat Bundles
The construction of sections of bundles with prescribed jet values plays a
fundamental role in problems of algebraic and complex geometry. When the jet
values are prescribed on a positive dimensional subvariety, it is handled by
theorems of Ohsawa-Takegoshi type which give extension of line bundle valued
square-integrable top-degree holomorphic forms from the fiber at the origin of
a family of complex manifolds over the open unit 1-disk when the curvature of
the metric of line bundle is semipositive. We prove here an extension result
when the curvature of the line bundle is only semipositive on each fiber with
negativity on the total space assumed bounded from below and the connection of
the metric locally bounded, if a square-integrable extension is known to be
possible over a double point at the origin. It is a Hensel-lemma-type result
analogous to Artin's application of the generalized implicit function theorem
to the theory of obstruction in deformation theory. The motivation is the need
in the abundance conjecture to construct pluricanonical sections from flatly
twisted pluricanonical sections. We also give here a new approach to the
original theorem of Ohsawa-Takegoshi by using the hyperbolic geometry of the
punctured open unit 1-disk to reduce the original theorem of Ohsawa-Takegoshi
to a simple application of the standard method of constructing holomorphic
functions by solving the d-bar equation with cut-off functions and additional
blowup weight functions
Sums and differences of four k-th powers
We prove an upper bound for the number of representations of a positive
integer as the sum of four -th powers of integers of size at most ,
using a new version of the Determinant method developed by Heath-Brown, along
with recent results by Salberger on the density of integral points on affine
surfaces. More generally we consider representations by any integral diagonal
form. The upper bound has the form , whereas earlier
versions of the Determinant method would produce an exponent for of order
in this case. Furthermore, we prove that the number of
representations of a positive integer as a sum of four -th powers of
non-negative integers is at most for
, improving upon bounds by Wisdom.Comment: 18 pages. Mistake corrected in the statement of Theorem 1.2. To
appear in Monatsh. Mat
On the ratio of consecutive gaps between primes
In the present work we prove a common generalization of Maynard-Tao's recent
result about consecutive bounded gaps between primes and on the
Erd\H{o}s-Rankin bound about large gaps between consecutive primes. The work
answers in a strong form a 60 years old problem of Erd\"os, which asked whether
the ratio of two consecutive primegaps can be infinitely often arbitrarily
small, and arbitrarily large, respectively
A remark on the trace-map for the Silver mean sequence
In this work we study the Silver mean sequence based on substitution rules by
means of a transfer-matrix approach. Using transfer-matrix method we find a
recurrence relation for the traces of general transfer-matrices which
characterizes electronic properties of the quasicrystal in question. We also
find an invariant of the trace-map.Comment: 5 pages, minor improvements in style and presentation of calculation
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