## Search

Now showing items 1-100 of 1927

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

We introduce algebraic dynamical systems, which consist of an action of a right LCM semigroup by injective endomorphisms of a group. To each algebraic dynamical system we associate a C*-algebra and describe it as a semigroup ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

We discuss the internal structure of graph products of right LCM semigroups and prove that there is an abundance of examples without property (AR). Thereby we provide the first examples of right LCM semigroups lacking ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We study the problem of optimal insider control of an SPDE (a stochastic evolution equation) driven by a Brownian motion and a Poisson random measure. Our optimal control problem is new in two ways:
- The controller has ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We show that a cubic fourfold F that is apolar to a Veronese surface has the property that its variety of power sums V SP ( F, 10) is singular along a K 3 surface of genus 20 which is the variety of power sums of a sextic ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We study how the geometry of a projective variety X is reflected in the positivity properties of the diagonal ΔX considered as a cycle on X×X. We analyze when the diagonal is big, when it is nef, and when it is rigid. In ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

By a memory mean-field process we mean the solution X(\cdot ) of a stochastic mean-field equation involving not just the current state X(t) and its law \mathcal {L}(X(t)) at time t, but also the state values X(s) and its ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The Grassmannian Gr(2,5) is embedded in ℙ9 via the Pl\"ucker embedding. The intersection of two general PGL(10)-translates of Gr(2,5) is a Calabi-Yau 3-fold X, and the intersection of the projective duals of the two ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We study the cones of surfaces on varieties of lines on cubic fourfolds and Hilbert schemes of points on K3 surfaces. From this we obtain new examples of nef cycles which fail to be pseudoeffective.

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Intrathecal drug and gene vector delivery is a procedure to release a solute within the cerebrospinal fluid. This procedure is currently used in clinical practice and shows promise for treatment of several central nervous ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We consider systems with memory represented by stochastic functional differential equations. Substantially, these are stochastic differential equations with coefficients depending on the past history of the process itself. ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

We give recursive formulas for the generating elements in the Milnor basis of the mod 2 motivic Steenrod algebra.
This research was first published in the New York Journal of Mathematics © 2017

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

This article studies singular mean field control problems and singular mean field two-players stochastic differential games. Both sufficient and necessary conditions for the optimal controls and for the Nash equilibrium ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Using Macaulay’s correspondence we study the family of Artinian Gorenstein local algebras with fixed symmetric Hilbert function decomposition. As an application we give a new lower bound for the dimension of cactus varieties ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

In this paper we derive optimal subspaces for Kolmogorov nn-widths in the L2 norm with respect to sets of functions defined by kernels. This enables us to prove the existence of optimal spline subspaces of arbitrarily high ...

(Doctoral thesis / Doktoravhandling, 2017)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The algebraic connectivity a(G) of a graph G is an important parameter, defined as the second smallest eigenvalue of the Laplacian matrix of G. If T is a tree, a(T) is closely related to the Perron values (spectral radius) ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

For stochastic conservation laws driven by a semilinear noise term, we propose a generalization of the Kružkov entropy condition by allowing the Kružkov constants to be Malliavin differentiable random variables. Existence ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

A well-known application of Malliavin calculus in mathematical finance is the probabilistic representation of option price sensitivities, the so-called Greeks, as expectation functionals that do not involve the derivative ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We consider the problem of finding a maximum k-regular induced subgraph of a graph G. Theoretical results are established to compare upper bounds obtained from different techniques, including bounds from quadratic programming, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

An alternating sign matrix , or ASM, is a (0,±1)(0,±1)-matrix where the nonzero entries in each row and column alternate in sign, and where each row and column sum is 1. We study the convex cone generated by ASMs of order ...

(Research report / Forskningsrapport, 2017)

There are many different numerical methods for solving the Navier-Stokes equations for problems with a free surface. Some examples are volume of fluid (VOF), Marker and cell (MAC), level set, smooth particle hydrodynamics ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We propose and investigate a valuation model for the income of selling tradeable green certificates (TGCs) in the Swedish–Norwegian market, formulated as a singular stochastic control problem. Our model takes into account ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We propose a boundary quotient diagram for right LCM semigroups with property (AR) that generalizes the boundary quotient diagram for N⋊N×. Our approach focuses on two important subsemigroups: the core subsemigroup and the ...

Strong solutions of d-dimensional SDE's with generalized drift and fractional Brownian initial noise

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

In this paper we prove the existence of strong solutions to a SDE with a generalized drift driven by a multidimensional fractional Brownian motion for small Hurst parameters H<1/2. Here the generalized drift is given as ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We lift ambit fields to a class of Hilbert space-valued volatility modulated Volterra processes. We name this class Hambit fields, and show that they can be expressed as a countable sum of weighted real-valued volatility ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We comment on the discretization of the Dirac equation using finite element spaces of differential forms. In order to treat perturbations by low order terms, such as those arising from electromagnetic fields, we develop ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Let ℓ be a prime and q=pν, where p is a prime different from ℓ. We show that the ℓ–completion of the nth stable homotopy group of spheres is a summand of the ℓ–completion of the (n,0) motivic stable homotopy group of spheres ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We show that a Hilbert scheme of conics on a Fano fourfold double cover of P2×P2 ramified along a divisor of bidegree (2,2) admits a P1-fibration with base being a hyper-Kähler fourfold. We investigate the geometry of such ...

(Chapter / Bokkapittel / SubmittedVersion, 2017)

Electricity infrastructure has become a critical element of modern industrial society. In order to model and analyse this infrastructure, identify weaknesses, and optimize performance, one needs to take into account its ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Background
It has been proposed that future reference genomes should be graph structures in order to better represent the sequence diversity present in a species. However, there is currently no standard ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We consider a scalar conservation law with zero-flux boundary conditions imposed on the boundary of a rectangular multidimensional domain. We study monotone schemes applied to this problem. For the Godunov version of the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Background: Using computational fluid dynamics (CFD) to compute the hemodynamics in cerebral aneurysms has received much attention in the last decade. The usability of these methods depends on the quality of the computations, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We determine the structure of equilibrium states for a natural dynamics on the boundary quotient diagram of C*-algebras for a large class of right LCM semigroups. The approach is based on abstract properties of the semigroup ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Proper orthogonal decomposition (POD) is applied to distinct data sets in order to characterize the propagation of error arising from basis truncation in the description of turbulence. Experimental data from stereo particle ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The notion of higher order dual varieties of a projective variety, introduced in \cite{P83}, is a natural generalization of the classical notion of projective duality. In this paper we present geometric and combinatorial ...

(Research report / Forskningsrapport, 2017)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Versatile instruments assembled from off-the-shelf sensors and open-source electronics are used to record wave propagation and damping measured by Inertial Motion Units (IMUs) in a grease ice slick near the shore in ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

Traditional programs based on feature engineering are under performing on a steadily increasing number of tasks compared with Artificial Neural Networks (ANNs), in particular for image analysis. Image analysis is widely ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The directional wave spectra in sea ice are an important aspect of wave evolution and can provide insights into the dominant components of wave dissipation, that is, dissipation due to scattering or dissipation due to ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The attenuation of surface gravity waves is an important process associated with air–sea and wave–current interactions. Here we investigate experimentally the attenuation of monochromatic surface gravity waves due to the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Landslides are the second-most important cause of tsunamis after earthquakes, and their potential for generating large tsunamis depend on the slide process. Among the world's largest submarine landslides is the Storegga ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We prove that all moment varieties of univariate Gaussian mixtures have the expected dimension. Our approach rests on intersection theory and Terracini’s classification of defective surfaces. The analogous identifiability ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The Lagrangian paths, horizontal Lagrangian drift velocity, U L , and the Lagrangian excess period, T L − T 0 , where T L is the Lagrangian period and T 0 the Eulerian linear period, are obtained by ...

(Chapter / Bokkapittel / SubmittedVersion; Peer reviewed, 2017)

With the shenfun Python module (github.com/spectralDNS/shenfun) an effort is made towards automating the implementation of the spectral Galerkin method for simple tensor product domains, consisting of (currently) one ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

This paper proposes a Finite Difference Multilevel Monte Carlo algorithm for degener- ate parabolic convection diffusion equations where the convective and diffusive fluxes are allowed to be random. We establish a notion ...

(Doctoral thesis / Doktoravhandling, 2016)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

Detailed observations of the diurnal jet, a surface intensification of the wind-driven current associated with the diurnal cycle of sea surface temperature (SST), were obtained during August and September 2012 in the ...

(Doctoral thesis / Doktoravhandling, 2016)

(Doctoral thesis / Doktoravhandling, 2016)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We prove that the Farrell–Jones assembly map for connective algebraic K -theory is rationally injective, under mild homological finiteness conditions on the group and assuming that a weak version of the Leopoldt–Schneider ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

Biot's consolidation model in poroelasticity has a number of applications in science, medicine, and engineering. The model depends on various parameters, and in practical applications these parameters range over several ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We study stochastic differential games of jump diffusions, where the players have access to inside information. Our approach is based on anticipative stochastic calculus, white noise, Hida–Malliavin calculus, forward ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

libRadtran is a widely used software package for radiative transfer calculations. It allows one to compute (polarized) radiances, irradiance, and actinic fluxes in the solar and thermal spectral regions. libRadtran has ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

For many high-dimensional studies, additional information on the variables, like (genomic) annotation or external p-values, is available. In the context of binary and continuous prediction, we develop a method for adaptive ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

The final publication is available at IOS Press.

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

We combine stochastic control methods, white noise analysis, and Hida–Malliavin calculus applied to the Donsker delta functional to obtain explicit representations of semimartingale decompositions under enlargement of ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We prove that if a closed subset X of the Baire space is searchable in the sense of Escardó [Logical Methods in Computer Science 4(3) (2008), 3], and by a functional definable in Gödel’s T, then X is countable, and the ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

Direct Numerical Simulations (DNS) of the Navier Stokes equations is an invaluable research tool in fluid dynamics. Still, there are few publicly available research codes and, due to the heavy number crunching implied, ...

(Research report / Forskningsrapport, 2016)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

Objective A number of observational studies have shown an inverse association between circulating 25-hydroxyvitamin D and total mortality, but a reverse J-shaped association has also been reported. In a large nested ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

In the present paper, a three-component, stationary, multistate flow network system is studied. Detailed costs and incomes are specified. The aim is to minimize the expected total net loss with respect to the expected times ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We investigate the K -theory of unital UCT Kirchberg algebras QS arising from families S of relatively prime numbers. It is shown that K∗(QS) is the direct sum of a free abelian group and a torsion group, each of which is ...

(Chapter / Bokkapittel / PublishedVersion; Peer reviewed, 2016)

We introduce Bichromatic Synthetic Schlieren (BiCSS) for instantaneous surface measurements, in where we use two simultaneous images taken at blue and near infrared wavelengths, making use of that refractive index variation ...

(Doctoral thesis / Doktoravhandling, 2016)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

Complexes of discrete distributional differential forms are introduced into finite element exterior calculus. Thus, we generalize a notion of Braess and Schöberl, originally studied for a posteriori error estimation. We ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We consider the pricing problem facing a seller of a contingent claim. We assume that this seller has some general level of partial information, and that he is not allowed to sell short in certain assets. This pricing ...

(Doctoral thesis / Doktoravhandling, 2016)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We show that a pseudoeffective R-divisor has numerical dimension 0 if it is numerically trivial on a subvariety with ample normal bundle. This implies that the cycle class of a curve with ample normal bundle is big, which ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

Within the framework of finite element systems, we show how spaces of differential forms may be constructed, in such a way that they are equipped with commuting interpolators and contain prescribed functions, and are minimal ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We show how the high order finite element spaces of differential forms due to Raviart-Thomas-Nédelec-Hiptmair fit into the framework of finite element systems, in an elaboration of the finite element exterior calculus of ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We introduce the notion of accurate foundation sets and the accurate refinement property for right LCM semigroups. For right LCM semigroups with this property, we derive a more explicit presentation of the boundary quotient. ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

In this paper we continue our study of logarithmic topological Hochschild homology. We show that the inclusion of the connective Adams summand ℓ into the p-local complex connective K-theory spectrum ku(p), equipped with ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

A matrix with a nonzero nonnegative vector in its null space is called central . We study classes of central matrices having zero column sums. The study is motivated by an engineering application concerning induction ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We initiate the study of the internal structure of C*-algebras associated to a left cancellative semigroup in which any two principal right ideals are either disjoint or intersect in another principal right ideal; these ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

The Bruhat order is defined in terms of an interchange operation on the set of permutation matrices of order n which corresponds to the transposition of a pair of elements in a permutation. We introduce an extension of ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We study the a priori error analysis of finite element methods for Biot’s consolidation model. We consider a formulation which has the stress tensor, the fluid flux, the solid displacement, and the pore pressure as unknowns. ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

A matrix of the form A = BBT where B is nonnegative is called completely positive (CP). Berman and Xu (2005) investigated a subclass of CP-matrices, called f0, 1g-completely positive matrices. We introduce a related concept ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

We treat a stochastic integration theory for a class of Hilbert-valued, volatility-modulated, conditionally Gaussian Volterra processes. We apply techniques from Malliavin calculus to define this stochastic integration as ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We classify up to isomorphism all non-Kac compact quantum groups with the same fusion rules and dimension function as SU(n). For this we first prove, using categorical Poisson boundary, the following general result. Let G ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

Given a Hopf algebra A graded by a discrete group together with an action of the same group preserving the grading, we define a new Hopf algebra, which we call the graded twisting of A. If the action is by adjoint maps, ...

(Journal article / Tidsskriftartikkel / SubmittedVersion; Peer reviewed, 2016)

We consider Dolbeault–Dirac operators on quantized irreducible flag manifolds as defined by Krähmer and Tucker-Simmons. We show that, in general, these operators do not satisfy a formula of Parthasarathy–type. This is a ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

Motivated by the relation between the Drinfeld double and central property (T) for quantum groups, given a rigid C*-tensor category C and a unitary half-braiding on an ind-object, we construct a *-representation of the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

We construct a new 20-dimensional family of projective six-dimensional irreducible holomorphic symplectic manifolds. The elements of this family are deformation equivalent with the Hilbert scheme of three points on a K3 ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

This study presents an experimental investigation of plunging breakers on a sloping beach with an inclination of 5.1°. The incident waves are solitary waves with various amplitudes from non-breaking waves to plunging ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

A celebrated financial application of convex duality theory gives an explicit relation between the following two quantities:
(i) The optimal terminal wealth X^*(T) : = X_{\varphi ^*}(T) of the problem to maximize the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We prove a verification theorem for a class of singular control problems which model optimal harvesting with density-dependent prices or optimal dividend policy with capital-dependent utilities. The result is applied to ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

We study a coupled system of controlled stochastic differential equations (SDEs) driven by a Brownian motion and a compensated Poisson random measure, consisting of a forward SDE in the unknown process X(t) and a predictive ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

The admission flow generated by a parallel valve diesel engine cylinder head was investigated by planar and stereoscopic Particle Image Velocimetry in a steady flow test bench through measurements in the swirl and tumble ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)

Observations of wave propagation in landfast ice were obtained in Tempelfjorden, Svalbard during March 2015. Wave motion was measured near the ice edge using inertial motion units and consisted of a combination of swell ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2015)

We show how a stochastic version of the Lagrange multiplier method can be combined with the stochastic maximum principle for jump diffusions to solve certain constrained stochastic optimal control problems. Two different ...

(Doctoral thesis / Doktoravhandling, 2015)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2015)

The purpose of this paper is to discuss the construction of a linear operator, referred to as the bubble transform, which maps scalar functions defined on Ω⊂Rn into a collection of functions with local support. In fact, ...

(Research report / Forskningsrapport, 2015)

We study a hierarchical dynamic state-space model for abundance estimation. A generic data fusion approach for combining computer simulated posterior samples of catch output data with observed re- search survey indices ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2015)

The canonical map from the Kan subdivision of a product of finite simplicial sets to the product of the Kan subdivisions is a simple map, in the sense that its geometric realization has contractible point inverses.
First ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)

The construction of projection operators, which commute with the exterior derivative and at the same time are bounded in the proper Sobolev spaces, represents a key tool in the recent stability analysis of finite element ...

(Doctoral dissertation / Doktoravhandling, 2015)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)

Based on forward curves modelled as Hilbert-space valued processes, we analyze the pricing of various options relevant in energy markets. In particular, we connect empirical evidence about energy forward prices known from ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2015)

We analyze cointegration in commodity markets, and propose a parametric class of pricing measures which preserves cointegration for forward prices with fixed time to maturity. We present explicit expressions for the term ...

(Research report / Forskningsrapport, 2015)

Quantifying operational risk exposure typically involves gathering information from several sources, including historical data as well as subjective assessments. Using historical data one can estimate both an incident ...