Results for "Florian Trybel"

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Pressure induced Hydrogen-Hydrogen interaction in metallic FeH revealed by NMRFeb 08 2019Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges. Here, we present ... More
Beyond-MSSM Higgs sectorsSep 25 2014Oct 28 2014This is a compact overview of Higgs sectors in extensions of the MSSM. The focus is on the summary of the main features of models with additional singlets and triplets as well as of models with Dirac gauginos. In addition, also important aspects of models ... More
SARAH 3.2: Dirac Gauginos, UFO output, and moreJul 04 2012Feb 12 2013SARAH is a Mathematica package optimized for the fast, efficient and precise study of supersymmetric models beyond the MSSM: a new model can be defined in a short form and all vertices are derived. This allows SARAH to create model files for FeynArts/FormCalc, ... More
Challenge IEEE-ISBI/TCB : Application of Covariance matrices and wavelet marginalsOct 10 2014This short memo aims at explaining our approach for the challenge IEEE-ISBI on Bone Texture Characterization. In this work, we focus on the use of covariance matrices and wavelet marginals in an SVM classifier.
The Picard Group of Various Families of $(\mathbb{Z}/2\mathbb{Z})^{4}$-invariant Quartic K3 SurfacesNov 05 2015The subject of this paper is the study of various families of quartic K3 surfaces which are invariant under a certain $(\mathbb{Z}/2\mathbb{Z})^{4}$ action. In particular, we describe families whose general member contains $8,16,24$ or $32$ lines as well ... More
The Impact of Credit Risk and Implied Volatility on Stock ReturnsMay 30 2010This paper examines the possibility of using derivative-implied risk premia to explain stock returns. The rapid development of derivative markets has led to the possibility of trading various kinds of risks, such as credit and interest rate risk, separately ... More
Warped Extra Dimensions: Flavor, Precision Tests and Higgs PhysicsDec 29 2011In this thesis, the phenomenology of the Randall-Sundrum setup is investigated. In this context models with and without an enlarged SU(2)_L x SU(2)_R x U(1)_X x P_{LR} gauge symmetry, which removes corrections to the T parameter and to the Z b_L \bar ... More
Basic Orders for Defect Two Blocks of $\Z_p\Sym_n$Nov 30 2010We show how basic orders for defect two blocks of symmetric groups over the ring of $p$-adic integers can be constructed by purely combinatorial means.
Fuzzy Characterization of Near-Earth-AsteroidsMay 23 2009Due to close encounters with the inner planets, Near-Earth-Asteroids (NEAs) can have very chaotic orbits. Because of this chaoticity, a statistical treatment of the dynamical properties of NEAs becomes difficult or even impossible. We propose a new way ... More
Iteratively reweighted adaptive lasso for conditional heteroscedastic time series with applications to AR-ARCH type processesFeb 23 2015Dec 05 2015Shrinkage algorithms are of great importance in almost every area of statistics due to the increasing impact of big data. Especially time series analysis benefits from efficient and rapid estimation techniques such as the lasso. However, currently lasso ... More
Non-conservative Lagrangian method for half-dark solitons in spinor non-equilibrium Polariton condensatesJan 08 2015In this work I introduce a powerful analytical method to analyze states of non-equilibrium polariton Bose-Einstein condensates (BEC). It is shown that the condensate wave functions carrying dark solitons and half-dark solitons can be expressed in terms ... More
Gaussian impurity moving through a Bose-Einstein superfluidOct 13 2016Oct 21 2016In this paper a Gaussian impurity moving through an equilibrium Bose-Einstein condensate at T = 0 is studied. The problem can be described by a Gross-Pitaevskii equation, which is solved perturbatively. The analysis is done for systems of 2 and 3 spatial ... More
Confinement for Active ObjectsMay 05 2014In this paper, we provide a formal framework for the security of distributed active objects. Active objects communicate asynchronously implementing method calls via futures. We base the formal framework on a security model that uses a semi-lattice to ... More
The CMS Particle Flow AlgorithmJan 31 2014A particle flow event-reconstruction algorithm has been successfully deployed in the CMS experiment and is nowadays used by most of the analyses. It aims at identifying and reconstructing individually each particle arising from the LHC proton-proton collision, ... More
Bose-Einstein Condensates with Derivative and Long-Range Interactions as Set-Ups for Analog Black HolesDec 10 2013Sep 30 2014General types of Bose-Einstein condensates are considered. The formation of black-hole analogues is examined for both short- and long-range interactions for arbitrary spatial dimensions greater than two. The former case includes non-linear derivative ... More
Cycle modules and the intersection A-infinity algebraJun 27 2009Given a cycle module M with a ring structure we show that the cycle complex with coefficients in M of a smooth scheme of finite type over a field has a A-infinity algebra structure. In the case of Milnor K-theory this gives a homotopy model for the classical ... More
Reverse mathematics of the finite downwards closed subsets of $\mathbb{N}^k$ ordered by inclusionOct 04 2016Nov 15 2016We show that the well-partial orderedness of the finite downwards closed subsets of $\mathbb{N}^k$ ,ordered by inclusion, is equivalent to the well-foundedness of the ordinal $\omega^{\omega^\omega}$. This was conjectured to be the case by Hatzikiriakou ... More
The integral polytope groupMay 04 2016Apr 25 2017We show that the Grothendieck group associated to integral polytopes in $\mathbb{R}^n$ is free-abelian by providing an explicit basis. Moreover, we identify the involution on this polytope group given by reflection about the origin as a sum of Euler characteristic ... More
Complexity theory for spaces of integrable functionsDec 19 2016Sep 09 2017This paper investigates second-order representations in the sense of Kawamura and Cook for spaces of integrable functions that regularly show up in analysis. It builds upon prior work about the space of continuous functions on the unit interval: Kawamura ... More
The Iwasawa Main Conjecture for elliptic curves at odd supersingular primesOct 31 2016In this paper, we prove the Iwasawa main conjecture for elliptic curves at an odd supersingular prime p. Some consequences are the p-parts of the leading term formulas in the Birch and Swinnerton-Dyer conjectures for analytic rank 0 or 1.
Alternation Is Strict For Higher-Order Modal Fixpoint LogicSep 14 2016We study the expressive power of Alternating Parity Krivine Automata (APKA), which provide operational semantics to Higher-Order Modal Fixpoint Logic (HFL). APKA consist of ordinary parity automata extended by a variation of the Krivine Abstract Machine. ... More
Global deformations of certain rational almost homogeneous projective bundlesJul 26 2016We study global deformations of certain projective bundles over projective spaces. We show that any projective global deformation of a projective bundle over $\bP^1$ carries the structure of a projective bundle over some projective space. Furthermore, ... More
A formulation for p-adic versions of the Birch and Swinnerton-Dyer conjectures in the supersingular caseDec 31 2015Given an elliptic curve E and a prime p of (good) supersingular reduction, we formulate p-adic analogues of the Birch and Swinnerton-Dyer conjecture using a pair of Iwasawa functions L^\sharp(E,T) and L^\flat(E,T). They are equivalent to the conjectures ... More
The Shafarevich-Tate group in cyclotomic Z_p-extensions at supersingular primesJun 10 2011We study the asymptotic growth of the p-primary component of the Shafarevich-Tate group in the cyclotomic direction at any odd prime of good supersingular reduction, generalizing work of Kobayashi. This explains formulas obtained by Kurihara, Perrin-Riou, ... More
The $L^2$-torsion polytope of amenable groupsApr 24 2017Jan 29 2018We introduce the notion of groups of polytope class and show that torsion-free amenable groups satisfying the Atiyah Conjecture possess this property. A direct consequence is the homotopy invariance of the $L^2$-torsion polytope among $G$-CW-complexes ... More
Reopen parameter regions in Two-Higgs Doublet ModelsMay 10 2017Dec 06 2017The stability of the electroweak potential is a very important constraint for models of new physics. At the moment, it is standard for Two-Higgs doublet models (THDM), singlet or triplet extensions of the standard model to perform these checks at tree-level. ... More
Filtering out the cosmological constant in the Palatini formalism of modified gravityJul 15 2010Jan 20 2011According to theoretical physics the cosmological constant (CC) is expected to be much larger in magnitude than other energy densities in the universe, which is in stark contrast to the observed Big Bang evolution. We address this old CC problem not by ... More
Gravity and Quantum Fields in Discrete Space-TimesOct 27 2006In a 6D model, where the extra dimensions form a discretised curved disk, we investigate the mass spectra and profiles of gravitons and Dirac fermions. The discretisation is performed in detail leading to a star-like geometry. In addition, we use the ... More
Greedy energy minimization can count in binary: point charges and the van der Corput sequenceMay 23 2019This paper establishes a connection between a problem in Potential Theory and Mathematical Physics, arranging points so as to minimize an energy functional, and a problem in Combinatorics and Number Theory, constructing 'well-distributed' sequences of ... More
Representing Isabelle in LFSep 14 2010LF has been designed and successfully used as a meta-logical framework to represent and reason about object logics. Here we design a representation of the Isabelle logical framework in LF using the recently introduced module system for LF. The major novelty ... More
On $α$-largeness and the Paris-Harrington principle in $\mathrm{RCA}_0$ and $\mathrm{RCA}_0^{\displaystyle{*}}$Nov 28 2016Jul 14 2018We examine, within $\mathrm{RCA}_0$, the treatment by Ketonen and Solovay on the use of $\alpha$-largeness for giving an upper bound for the Paris--Harrington principle. This proof works fine in $\mathrm{RCA}_0^{\displaystyle{*}}$ for every fixed standard ... More
Phase transition results for three Ramsey-like theoremsMar 22 2016We classify a sharp phase transition threshold for Friedman's finite adjacent Ramsey theorem. We extend the method for showing this result to two previously known classifications involving Ramsey theorem variants: the Paris--Harrington theorem and the ... More
On "finitary" Ramsey's theoremAug 09 2015Nov 29 2016We examine a version of Ramsey's theorem based on Tao, Gaspar and Kohlenbach's "finitary" infinite pigeonhole principle.We will show that the "finitary" infinite Ramsey's theorem naturally gives rise to statements at the level of the infinite Ramsey's ... More
The inverse problem for Schwinger pair productionSep 29 2015Dec 22 2015The production of electron-positron pairs in time-dependent electric fields (Schwinger mechanism) depends non-linearly on the applied field profile. Accordingly, the resulting momentum spectrum is extremely sensitive to small variations of the field parameters. ... More
Generalized orthogonal matching pursuit for multiple measurements - A structural approachMay 23 2017Sparse data approximation has become a popular research topic in signal processing. However, in most cases only a single measurement vector (SMV) is considered. In applications, the multiple measurement vector (MMV) case is more usual, i.e., the sparse ... More
The weight in a Serre-type conjecture for tame n-dimensional Galois representationsMar 03 2008Jul 04 2011We formulate a Serre-type conjecture for n-dimensional Galois representations that are tamely ramified at p. The weights are predicted using a representation-theoretic recipe. For n = 3 some of these weights were not predicted by the previous conjecture ... More
Lifting of morphisms to quotient presentationsSep 30 2002In this article we investigate algebraic morphisms between toric varieties. Given presentations of toric varieties as quotients we are interested in the question when a morphism admits a lifting to these quotient presentations. We show that this can be ... More
Cops, robbers, and infinite graphsOct 30 2014Mar 30 2015Cops and robbers is a game between two players, where one tries to catch the other by moving along the edges of a graph. It is well known that on a finite graph the cop has a winning strategy if and only if the graph is constructible and that finiteness ... More
Counting Algebraic Curves with Tropical GeometryJun 09 2012Tropical geometry is a piecewise linear "shadow" of algebraic geometry. It allows for the computation of several cohomological invariants of an algebraic variety. In particular, its application to enumerative algebraic geometry led to significant progress. ... More
Monoide des enlacements et facteurs orthogonaux (Monoids of linking pairings and orthogonal summands)Mar 14 2005Jun 17 2005A linking pairing is a symetric bilinear pairing lambda: GxG --> Q/Z on a finite abelian group. The set of isomorphism classes of linking pairings is a non-cancellative monoid E under orthogonal sum, which is infinitely generated and infinitely related. ... More
Torsion bounds for elliptic curves and Drinfeld modulesOct 17 2008We derive asymptotically optimal upper bounds on the number of L-rational torsion points on a given elliptic curve or Drinfeld module defined over a finitely generated field K, as a function of the degree [L:K]. Our main tool is the adelic openness of ... More
Intersection patterns of finite sets and of convex setsJul 04 2016The main result is a common generalization of results on lower bounds for the chromatic number of r-uniform hypergraphs and some of the major theorems in Tverberg-type theory, which is concerned with the intersection pattern of faces in a simplicial complex ... More
Uniformly distributed sequences in the orthogonal group and on the Grassmannian manifoldMay 16 2014Sep 17 2014Quasi-Monte Carlo methods replaced classical Monte Carlo methods in many areas of numerical analysis over the last decades. The purpose of this paper is to extend quasi-Monte Carlo methods into a new direction. We construct and implement a uniformly distributed ... More
Lévy processes with values in locally convex Suslin spacesOct 02 2015We provide a L\'evy-It\^o decomposition of sample paths of L\'evy processes with values in complete locally convex Suslin spaces. This class of state spaces contains the well investigated examples of separable Banach spaces, as well as Fr\'echet or distribution ... More
When is an origami set a ring?Apr 27 2018Starting with a flat sheet of paper, points can be constructed as the intersection of two folds. The set of constructible points clearly depends on which folds are admissible. In this paper, we study the situation where a fold is admissible if its slope ... More
Attack Trees in IsabelleMar 17 2018May 15 2018In this paper, we present a proof theory for attack trees. Attack trees are a well established and useful model for the construction of attacks on systems since they allow a stepwise exploration of high level attacks in application scenarios. Using the ... More
The CLIC Detector ConceptFeb 16 2018The Compact Linear Collider (CLIC) is a concept for a future linear collider that would provide e$^+$e$^-$ collisions at up to 3 TeV. The physics aims require a detector system with excellent jet energy and track momentum resolution, highly efficient ... More
Testability of the exclusion restriction in continuous instrumental variable modelsJun 25 2018In this note we prove Pearl's conjecture, showing that the exclusion restriction of an instrument cannot be tested without structural assumptions in general instrumental variable models with a continuously distributed endogenous variable. This stands ... More
Accessing Masses Beyond Collider Reach - in EFTNov 08 2017We demonstrate how masses of new states, beyond direct experimental reach, could nevertheless be extracted in the framework of effective field theory (EFT), given broad assumptions on the underlying UV physics, however not sticking to a particular setup ... More
A projector-based convergence proof of the Ginelli algorithm for covariant Lyapunov vectorsFeb 23 2018May 29 2019Linear perturbations of solutions of dynamical systems exhibit different asymptotic growth rates, which are naturally characterized by so-called covariant Lyapunov vectors (CLVs). Due to an increased interest of CLVs in applications, several algorithms ... More
Brownian Motions on Metric Graphs with Non-Local Boundary Conditions I: CharacterizationMay 17 2018A classification for Brownian motions on metric graphs, that is, right continuous strong Markov processes which behave like a one-dimensional Brownian motion on the edges and feature effects like Walsh skewness, stickiness and jumps at the vertices, is ... More
Model-Independent Pricing of Asian Options via Optimal Martingale TransportDec 03 2014In this article we discuss the problem of calculating optimal model-independent (robust) bounds for the price of Asian options with discrete and continuous averaging. We will give geometric characterisations of the maximising and the minimising pricing ... More
Computing Node Polynomials for Plane CurvesJun 01 2010Mar 09 2011According to the G\"ottsche conjecture (now a theorem), the degree N^{d, delta} of the Severi variety of plane curves of degree d with delta nodes is given by a polynomial in d, provided d is large enough. These "node polynomials" N_delta(d) were determined ... More
Reverse mathematics of the finite downwards closed subsets of $\mathbb{N}^k$ ordered by inclusion and adjacent Ramsey for fixed dimensionOct 04 2016Oct 04 2017We show that the well-partial orderedness of the finite downwards closed subsets of $\mathbb{N}^k$ ,ordered by inclusion, is equivalent to the well-foundedness of the ordinal $\omega^{\omega^\omega}$. This was conjectured to be the case by Hatzikiriakou ... More
Symmetries, psudosymmetries and conservation laws in Lagrangian and Hamiltonian $k$-symplectic formalismsOct 16 2014In this paper we will present Lagrangian and Hamiltonian $k$-symplectic formalisms, we will recall the notions of symmetry and conservation law and we will define the notion of pseudosymmetry as a natural extension of symmetry. Using symmetries and pseudosymmetries, ... More
An Application of Fixed-point Theory to Probabilistic Social ChoiceOct 22 2014Nov 26 2014The purpose of this note is to prove the existence of a randomized mechanism, a social decision scheme (SDS), with desirable fairness, efficiency, and strategyproofness properties unmatched by all known SDSs. In particular, we disprove a conjecture by ... More
Exploring new models in all detail with SARAHMar 13 2015I give an overview about the features the Mathematica package SARAH provides to study new models. In general, SARAH can handle a wide range of models beyond the MSSM coming with additional chiral superfields, extra gauge groups, or distinctive features ... More
From Superpotential to Model Files for FeynArts and CalcHep/CompHepSep 15 2009SARAH is a Mathematica package for building and studying supersymmetric models. It calculates for a given superpotential and gauge sector the full Lagrangian of a model. With the new version of SARAH it is possible to calculate automatically all interactions ... More
Warum Astrologie nicht funktionieren kannAug 28 2011There exists many different versions of astrology that are different from each other and sometimes even in conflict with each other. But the basis of every astrological system is the assumption of a connection between the motion of celestial bodies and ... More
Gaussian impurity moving through a Bose-Einstein superfluidOct 13 2016In this paper a Gaussian impurity moving through an equilibrium Bose-Einstein condensate at T = 0 is studied. The problem can be described by a Gross-Pitaevskii equation, which is solved perturbatively. The analysis is done for systems of 2 and 3 spatial ... More
Cosmology with the 6-degree Field Galaxy SurveyMar 13 2013This thesis presents the analysis of the clustering of galaxies in the 6dF Galaxy Survey (6dFGS). At large separation scales the baryon acoustic oscillation (BAO) signal is detected which allows to make an absolute distance measurement at $z_{\rm eff} ... More
The p-adic group ring of SL_2(p^f)Jan 31 2013In this article we show that the $\Z_p[\zeta_{p^f-1}]$-order $\Z_p[\zeta_{p^f-1}]\SL_2(p^f)$ can be recognized among those orders whose reduction modulo $p$ is isomorphic to $\F_{p^f}\SL_2(p^f)$ using only ring-theoretic properties (in other words we ... More
A finiteness condition on local cohomology in positive characteristicJan 25 2011Apr 25 2011In this paper we present a condition on a local Cohen-Macaulay F-injective ring of positive characteristic $p > 2$ which implies that its top local cohomology module with support in the maximal ideal has finitely many Frobenius compatible submodules.
Random Fruits on the Zielonka TreeFeb 16 2009Stochastic games are a natural model for the synthesis of controllers confronted to adversarial and/or random actions. In particular, $\omega$-regular games of infinite length can represent reactive systems which are not expected to reach a correct state, ... More
Galois groups associated to generic Drinfeld modules and a conjecture of AbhyankarMar 10 2013Aug 19 2015Let $\phi$ be a rank $r$ Drinfeld $\BF_q[T]$-module determined by $\phi_T(X) = TX+g_1X^q+...+g_{r-1}X^{q^{r-1}}+X^{q^r}$, where $g_1,...,g_{r-1}$ are algebraically independent over $\BF_q(T)$. Let $N\in\BF_q[T]$ be a polynomial, and $k/\BF_q$ an algebraic ... More
Statistical analysis of a subset of the string theory landscapeOct 20 2008An analysis of a special class of type II string theory compactifications is presented. We focus on recent work in one particular orientifold background of intersecting brane models and the resulting four dimensional gauge group and matter content. Special ... More
Gauge sector statistics of intersecting D-brane modelsAug 31 2006Mar 02 2007In this article, which is based on the first part of my PhD thesis, I review the statistics of the open string sector in T^6/(Z_2xZ_2) orientifold compactifications of the type IIA string. After an introduction to the orientifold setup, I discuss the ... More
Phenomenology of jet physics in the BFKL formalism at NLOMar 19 2007We study jet physics in the high energy regime of QCD. Based on the NLO BFKL equation, we construct a vertex for the production of a jet at central rapidity in k_T-factorization. A jet algorithm is introduced, and we take special care of the separation ... More
On "finitary" Ramsey's theoremAug 09 2015Jul 05 2016We examine a version of Ramsey's theorem based on Tao, Gaspar and Kohlenbach's "finitary" infinite pigeonhole principle.We will show that the "finitary" infinite Ramsey's theorem naturally gives rise to statements at the level of the infinite Ramsey's ... More
Lower bounds on the size of general Schrödinger-cat states from experimental dataOct 11 2016Oct 12 2016Experimental progress with meso- and macroscopic quantum states (i.e., general Schrodinger-cat states) was recently accompanied by theoretical proposals on how to measure the merit of these efforts. So far, experiment and theory were disconnected as theoretical ... More
Total weight choosability in HypergraphsDec 22 2013A total weighting of the vertices and edges of a hypergraph is called vertex-coloring if the total weights of the vertices yield a proper coloring of the graph, i.e., every edge contains at least two vertices with different weighted degrees. In this note ... More
On pairs of p-adic analogues of the conjectures of Birch and Swinnerton-DyerNov 06 2012Dec 31 2015For a weight two modular form and a good prime $p$, we construct a vector of Iwasawa functions $(L_p^\sharp,L_p^\flat)$. In the elliptic curve case, we use this vector to put the $p$-adic analogues of the conjectures of Birch and Swinnerton-Dyer for ordinary ... More
Tutorial to SARAHMar 18 2016I give in this brief tutorial a short practical introduction to the Mathematica package SARAH. First, it is shown how an existing model file can be changed to implement a new model in SARAH. In the second part, masses, vertices and renormalisation group ... More
Intrinsic bottom and its impact on heavy new physics at the LHCJan 12 2016Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon splitting and do not ... More
On pairs of p-adic L-functions for weight two modular formsDec 31 2015The point of this paper is to give an explicit p-adic analytic construction of two Iwasawa functions L_p^\sharp(f,T) and L_p^\flat(f,T) for a weight two modular form \sum a_n q^n and a good prime p. This generalizes work of Pollack who worked in the supersingular ... More
The cosmological constant filter without big bang singularityAug 03 2011Oct 03 2011In the recently proposed cosmological constant (CC) filter mechanism based on modified gravity in the Palatini formalism, gravity in the radiation, matter and late-time de Sitter eras is insensitive to energy sources with the equation of state -1. This ... More
The cosmological constant and the relaxed universeOct 06 2010We study the role of the cosmological constant (CC) as a component of dark energy (DE). It is argued that the cosmological term is in general unavoidable and it should not be ignored even when dynamical DE sources are considered. From the theoretical ... More
$ψ$-Epistemic Models, Einsteinian Intuitions, and No-Gos. A Critical Study of Recent Developments on the Quantum StateMar 31 2016Apr 18 2016Quantum mechanics notoriously faces the measurement problem, the problem that if read thoroughly, it implies the nonexistence of definite outcomes in measurement procedures. A plausible reaction to this and to related problems is to regard a system's ... More
Positive orthogonal functionsOct 16 2015The existence or non-existence of positive orthogonal functions for subspaces of almost periodic functions has important applications in studying the oscillatory behavior of vibrations. Cazenave, Haraux and Komornik have obtained a number of theorems ... More
A New Tool for the study of the CP-violating NMSSMMar 24 2015Jun 22 2015Supersymmetric extensions of the Standard Model open up the possibility for new types of CP-violation. We consider the case of the Next-to-Minimal Supersymmetric Standard Model where, beyond the phases from the soft lagrangian, CP-violation could enter ... More
Decays of a NMSSM CP-odd Higgs in the low-mass regionDec 20 2016Mar 27 2017A popular regime in the NMSSM parameter space involves a light CP-odd Higgs $A_1$. This scenario has consequences for e.g. light singlino Dark Matter annihilating in the $A_1$-funnel. In order to confront the pseudoscalar to experimental limits such as ... More
Rooted induced trees in triangle-free graphsApr 09 2008Dec 15 2008For a graph $G$, let $t(G)$ denote the maximum number of vertices in an induced subgraph of $G$ that is a tree. Further, for a vertex $v\in V(G)$, let $t^v(G)$ denote the maximum number of vertices in an induced subgraph of $G$ that is a tree, with the ... More
The Distribution of Optimal Strategies in Symmetric Zero-sum GamesNov 18 2016Jul 10 2017Given a skew-symmetric matrix, the corresponding two-player symmetric zero-sum game is defined as follows: one player, the row player, chooses a row and the other player, the column player, chooses a column. The payoff of the row player is given by the ... More
Higher Heegner points on elliptic curves over function fieldsApr 16 2003Sep 22 2003Let E be a modular elliptic curve defined over a rational function field k of odd characteristic. We construct a sequence of Heegner points on E, defined over a $Z_p^{\infty}$-tower of finite extensions of k, and show that these Heegner points generate ... More
Firefighting on trees and Cayley graphsJul 05 2017We study Hartnell's firefighter problem on infinite trees and characterise the branching number in terms of the firefighting game. Using our results about trees, we give a partial answer to a question of Mart\'inez-Pedroza concerning firefighting on Cayley ... More
Combined degree and connectivity conditions for H-linked graphsJun 07 2012For a given multigraph H, a graph G is H-linked, if |G| \geq |H| and for every injective map {\tau}: V (H) \rightarrow V (G), we can find internally disjoint paths in G, such that every edge from uv in H corresponds to a {\tau} (u) - {\tau} (v) path. ... More
Schwinger effect in inhomogeneous electric fieldsJun 29 2011The vacuum of quantum electrodynamics is unstable against the formation of many-body states in the presence of an external electric field, manifesting itself as the creation of electron-positron pairs (Schwinger effect). This effect has been a long-standing ... More
Palindromes and orderings in Artin groupsOct 11 2004Mar 14 2005The braid group $B_{n}$, endowed with Artin's presentation, admits two distinguished involutions. One is the anti-automorphism ${\rm{rev}}: B_{n} \to B_{n}$, $v \mapsto \bar{v}$, defined by reading braids in the reverse order (from right to left instead ... More
Total Edge Irregularity Strength of Large GraphsJun 23 2010Let $m:=|E(G)|$ sufficiently large and $s:=(m-1)/3$. We show that unless the maximum degree $\Delta > 2s$, there is a weighting $w:E\cup V\to \{0,1,...,s\}$ so that $w(uv)+w(u)+w(v)\ne w(u'v')+w(u')+w(v')$ whenever $uv\ne u'v'$ (such a weighting is called ... More
Twist-Deformed Lorentzian Heisenberg-AlgebrasAug 10 2006The Moyal-Weyl quantization procedure is embedded into the twist formalism of vector fields on phase space. Double application of twists provide most general deformations of Minkowskian Heisenberg-algebras and corresponding quantizations of the Lorentz-algebra. ... More
A note on Gekeler's h-functionMay 09 2016We give a brief introduction to Drinfeld modular forms, concentrating on the many equivalent constructions of the form h of weight q+1 and type 1, to which we contribute some new characterizations involving Moore determinants, and an application to the ... More
Pro-l birational anabelian geometry over algebraically closed fields IJul 05 2003We consider function fields of transcendence degree at least 2 over algebraic closures of finite fields, and describe a functorial way to recover such function fields form their pro-l Galois theory.
A Satake isomorphism in characteristic pOct 23 2009Feb 02 2011Suppose that G is a connected reductive group over a p-adic field F, that K is a hyperspecial maximal compact subgroup of G(F), and that V is an irreducible representation of K over the algebraic closure of the residue field of F. We establish an analogue ... More
Implicit-explicit, realizability-preserving first-order scheme for moment models with Lipschitz-continuous source termsNov 04 2016We derive an implicit-explicit (IMEX), realizability-preserving first-order scheme for moment models with Lipschitz-continuous source terms. In contrast to fully-explicit schemes the time step does not depend on the physical parameters, removing the stiffness ... More
A note on the geometry of pseudoconvex domains of finite type in almost complex manifoldsAug 17 2010Let $D=\{\rho<0\}$ be a smooth domain of finite type in an almost complex manifold (M,J) of real dimension four. We assume that the defining function $\rho$ is J-plurisubharmonic on a neighborhood of $\overline{D}$. We study the asymptotic behavior of ... More
Pseudoconvex regions of finite D'Angelo type in four dimensional almost complex manifoldsOct 08 2007Let D be a J-pseudoconvex region in a smooth almost complex manifold (M,J) of real dimension four. We construct a local peak J-plurisubharmonic function at every boundary point p of finite D'Angelo type. As applications we give local estimates of the ... More
Forecasting Electricity Spot Prices using Lasso: On Capturing the Autoregressive Intraday StructureSep 07 2015Jan 23 2016In this paper we present a regression based model for day-ahead electricity spot prices. We estimate the considered linear regression model by the lasso estimation method. The lasso approach allows for many possible parameters in the model, but also shrinks ... More
On affine Tverberg-type results without continuous generalizationFeb 17 2017Recent progress building on the groundbreaking work of Mabillard and Wagner has shown that there are important differences between the affine and continuous theory for Tverberg-type results. These results aim to describe the intersection pattern of convex ... More
Explicit Drinfeld moduli schemes and Abhyankar's generalized iteration conjectureMar 22 2015Aug 19 2015Let $k$ be a field containing $\mathbb{F}_q$. Let $\psi$ be a rank $r$ Drinfeld $\mathbb{F}_q[t]$-module determined by $\psi_t(X) = tX+a_1X^q+\cdots+a_{r-1}X^{q^{r-1}}+X^{q^r}$, where $t,a_1,\ldots,a_{r-1}$ are algebraically independent over $k$. Let ... More
Strong test modules and multiplier idealsMar 26 2003We introduce the notion of strong test module and show that a large number of such modules appear in the tight closure theory of complete domains: the test ideal (this has already been known), the parameter test module, and the module of relative test ... More