arXiv
(422,153 recursos)
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Mostrando recursos 121 - 140 de 66,283
121.
Bounds for the Solutions of Cubic Diophantine Equations - Kleiman, Howard
The original version of this paper did not take into account that there may
be solutions (x_0, y_o)in Z X Z of f(x,y) = x^3 + p(y)x + q(y) = 0 even though
w_0 = (-3D(y_0))^(1/2) is irrational.
122.
On measures of unfairness and an optimal currency transaction tax - Herzberg, Frederik
The purpose of the present paper is the analysis of a model describing how
herd behaviour and self-fulfilling prophecies can influence currency exchange
rates, and what the impact of a currency transaction tax would be. These
considerations yield a stochastic differential equation that can be studied
using the methods of infinitesimal analysis. We will show, using a suitable
notion of unfairness for discounted price processes which measures the distance
from being a martingale, that the fairest tax rate is the maximal one subject
to the condition that it does not affect real-economic speculation.
123.
The fairest price of an asset in an environment of temporary arbitrage - Herzberg, Frederik
In practice there are temporary arbitrage opportunities arising from the fact
that prices for a given asset at different stock exchanges are not
instantaneously the same. We will show that even in such an environment there
exists a ``fairest measure'' (instead of a martingale measure), albeit not
necessarily unique. For this end, we define and analyse quantitative notions of
unfairness in complete as well as incomplete market settings.
124.
Smash products of E(1)-local spectra at an odd prime - Ganter, Nora
In 1996, Franke constructed a purely algebraic category that is equivalent as
a triangulated category to the E(n)-local stable homotopy category for n^2+n <
2p-2. The two categories are not Quillen equivalent, and his proof uses systems
of triangulated diagram categories rather than model categories. Our main
result is that in the case n=1 Franke's functor maps the derived tensor product
to the smash product. It can however not be an associative equivalence of
monoidal categories. The first part of our paper sets up a monoidal version of
Franke's systems of triangulated diagram categories and explores its
properties. The second part applies these results to the specific construction
of...
125.
SU(3)-structures on hypersurfaces of manifolds with G_2-structure - Cabrera, Francisco Martin
We study SU(3)-structures induced on orientable hypersurfaces of
seven-dimensional manifolds with G_2-structure. Taking Gray-Hervella types for
both structures into account, we relate the type of SU(3)-structure and the
type of G_2-structure with the shape tensor of the hypersurface. Additionaly,
we show how to compute the intrinsic SU(3)-torsion and the intrinsic
G_2-torsion by means of exterior algebra.
127.
Invariants of Lagrangian surfaces - Yau, Mei-Lin
We define a nonnegative integer $\la(L,L_0;\phi)$ for a pair of diffeomorphic
closed Lagrangian surfaces $L_0,L$ embedded in a symplectic 4-manifold $(M,\w)$
and a diffeomorphism $\phi\in\Diff^+(M)$ satisfying $\phi(L_0)=L$. We prove
that if there exists $\phi\in\Diff^+_o(M)$ with $\phi(L_0)=L$ and
$\la(L,L_0;\phi)=0$, then $L_0,L$ are symplectomorphic. We also define a second
invariant $n(L_1,L_0;[L_t])=n(L_1,L_0,[\phi_t])$ for a smooth isotopy
$L_t=\phi_t(L_0)$ between two Lagrangian surfaces $L_0$ and $L_1$ with $\la
(L_1,L_0;\phi_1)=0$, which serves as an obstruction of deforming $L_t$ to a
Lagrangian isotopy with $L_0,L_1$ preserved.
128.
Maps on posets, and blockers - Matveev, Andrey O.
An order-theoretic generalization of Seymour relations describing the
connection between the set-theoretic blocker, deletion, and contraction maps on
clutters, is presented.
129.
Generic Transfer for General Spin Groups - Asgari, Mahdi; Shahidi, Freydoon
We prove Langlands functoriality for the generic spectrum of general spin
groups (both odd and even). Contrary to other recent instances of
functoriality, our resulting automorphic representations on the general linear
group will not be self-dual. Together with cases of classical groups, this
completes the list of cases of split reductive groups whose L-groups have
classical derived groups. The important transfer from GSp(4) to GL(4) follows
from our result as a special case.
130.
A note on Alxesandrov type theorem for k-convex functions - Chaudhuri, Nirmalendu; Trudinger, Neil S.
In this note we show that $k$-convex functions on $\Bbb R^n$ are twice
differentiable almost everywhere for every positive integer $k>n/2$. This
generalizes the classical Alexsandrov's theorem for convex functions.
131.
A note on special duality triads and their operator valued counterparts - Borak, Ewa
We shall work with the so called duality triads following kwa\'sniewski. In
particular in this note we propose some extensions of them - hence we choose
such special class of triads that admit - all at once - a unified combinatorial
interpretation in a way konvalina does. The proposed extensions contain also
definition of operator valued arrays of konvalina-like coefficients - for the
sake of future investigation and applications.
132.
On primitive ideals in polynomial rings over nil rings - Smoktunowicz, Agata
Let R be a nil ring. We prove that primitive ideals in the polynomial ring
R[x] in one indeterminate over R are of the form I[x] for some ideals I of R.
133.
Dynamics of Interest Rate Curve by Functional Auto-Regression - Kargin, Vladislav; Onatski, Alexei
The paper uses functional auto-regression to predict the dynamics of interest
rate curve. It estimates the auto-regressive operator by extending methods of
the reduced-rank auto-regression to the functional data. Such an estimation
technique is better suited for prediction purposes as opposed to the methods
based either on principal components or canonical correlations. The consistency
of the estimator is proved using methods of operator theory. The estimation
method is used to analyze dynamics of Eurodollar futures rates. The results
suggest that future movements of interest rates are predictable at 1-year
horizons.
134.
Extending holomorphic mappings from subvarieties in Stein manifolds - Forstneric, Franc
Suppose that Y is a complex manifold with the property that any holomorphic
map from a compact convex set in a complex Euclidean space C^n (for any n) to Y
is a uniform limit of entire maps from C^n to Y. We prove that a holomorphic
map from a closed complex subvariety X_0 in a Stein manifold X to the manifold
Y extends to a holomorphic map of X to Y provided that it extends to a
continuous map. We then establish the equivalence of four Oka-type properties
of a complex manifold. We also generalize a theorem of Siu and Demailly on the
existence of open Stein...
135.
Holomorphic one-forms on varieties of general type - Hacon, Christopher D.; Kovács, Sándor J.
It has been conjectured that varieties of general type do not admit nowhere
vanishing holomorphic one-forms. We confirm this conjecture for smooth minimal
varieties and for varieties whose Albanese variety is simple.
136.
Maximal volume representations are fuchsian - Francaviglia, S.; Klaff, B.
We prove a volume-rigidity theorem for fuchsian representations of
fundamental groups of hyperbolic k-manifolds into Isom(H^n). Namely, we show
that if M is a complete hyperbolic k-manifold with finite volume, then the
volume of any representation of its fundamental group into Isom(H^n), 3 <= k <=
n, is less than the volume of M, and the volume is maximal if and only if the
representation is discrete, faithful and ``k-fuchsian''.
137.
Variations of a Coin-Removal Problem - Shelton, Kennan; Siler, Michael
Given a set of coins arranged in a line, we remove heads-up coins one at a
time and flip any adjacent coins after each removal. The coin-removal problem
is to determine for which arrangements of coins it is possible to remove all of
the coins. In this paper we consider a variation of the problem in which gaps
created by removing coins are eliminated by pushing the coins together. We
characterize the set of removable arrangements and show that this set forms a
regular language. We use a finite automaton to find a recursive formula for the
number of removable arrangements of different lengths.
138.
Rack and quandle homology - Jackson, Nicholas
The theory of rack and quandle modules is developed - in particular a tensor
product is defined, and shown to satisfy an appropriate adjointness condition.
Notions of free rack and quandle modules are introduced, and used to define an
enveloping object (the `rack algebra' or `wring') for a given rack or quandle.
These constructions are then used to define homology and cohomology theories
for racks and quandles which contain all currently-known variants.
140.
Eigenvalues of Hermitian matrices with positive sum of bounded rank - Buch, Anders Skovsted
We give a minimal list of inequalities characterizing the possible
eigenvalues of a set of Hermitian matrices with positive semidefinite sum of
bounded rank. This answers a question of A. Barvinok.
121.
