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Results for "Alfred Zimmermann"

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Microservices Migration in Industry: Intentions, Strategies, and ChallengesJun 11 2019To remain competitive in a fast changing environment, many companies started to migrate their legacy applications towards a Microservices architecture. Such extensive migration processes require careful planning and consideration of implications and challenges ... More
Assuring the Evolvability of Microservices: Insights into Industry Practices and ChallengesJun 12 2019While Microservices promise several beneficial characteristics for sustainable long-term software evolution, little empirical research covers what concrete activities industry applies for the evolvability assurance of Microservices and how technical debt ... More
On the use of Külshammer type invariants in representation theoryOct 29 2010Since 2005 a new powerful invariant of an algebra emerged using earlier work of Horv\'ath, H\'ethelyi, K\"ulshammer and Murray. The authors studied Morita invariance of a sequence of ideals of the centre of a finite dimensional algebra over a field of ... More
The Ring of Polynomial Functors of Prime DegreeApr 17 2013Aug 15 2013Let $\hat\Z_p$ be the ring of $p$-adic integers. We prove in the present paper that the category of polynomial functors from finitely generated free abelian groups to $\hat \Z_p$-modules of degree at most $p$ is equivalent to the category of finitely ... More
Simple transitive $2$-representations of left cell $2$-subcategories of projective functors for star algebrasMay 15 2018In this paper we study simple transitive $2$-representations of certain $2$-subcategories of the $2$-category of projective functors over a star algebra. We show that in the simplest case, which is associated to the Dynkin type $A_2$, simple transitive ... More
The real plane Cremona group is a non-trivial amalgamMay 21 2017Feb 08 2019We show that the real Cremona group of the plane is a non-trivial amalgam of two groups along their intersection.
A matrix-algebraic algorithm for the Riemannian logarithm on the Stiefel manifold under the canonical metricApr 18 2016Mar 17 2017We derive a numerical algorithm for evaluating the Riemannian logarithm on the Stiefel manifold with respect to the canonical metric. In contrast to the existing optimization-based approach, we work from a purely matrix-algebraic perspective. Moreover, ... More
Logarithmic Sobolev inequalities for mollified compactly supported measuresNov 05 2014We show that the convolution of a compactly supported measure on $\mathbb{R}$ with a Gaussian measure satisfies a logarithmic Sobolev inequality (LSI). We use this result to give a new proof of a classical result in random matrix theory that states that, ... More
Delay Games with WMSO+U Winning ConditionsDec 12 2014Sep 24 2015Delay games are two-player games of infinite duration in which one player may delay her moves to obtain a lookahead on her opponent's moves. We consider delay games with winning conditions expressed in weak monadic second order logic with the unbounding ... More
Exploring chance in NCAA basketballAug 19 2015There seems to be an upper limit to predicting the outcome of matches in (semi-)professional sports. Recent work has proposed that this is due to chance and attempts have been made to simulate the distribution of win percentages to identify the most likely ... More
A matrix-algebraic algorithm for the Riemannian logarithm on the Stiefel manifoldApr 18 2016May 09 2016We derive a numerical algorithm for evaluating the Riemannian logarithm on the Stiefel manifold with respect to the canonical metric. In contrast to the optimization-based approach known from the literature, we work from a purely matrix-algebraic perspective. ... More
A closed-form update for orthogonal matrix decompositions under arbitrary rank-one modificationsNov 22 2017Jun 08 2018We consider rank-one adaptations $X_{new} = X+ab^T$ of a given matrix $X\in \mathbb{R}^{n\times p}$ with known matrix factorization $X = UW$, where $U\in\mathbb{R}^{n\times p}$ is column-orthogonal, i.e. $U^TU=I$. Arguably the most important methods that ... More
Invariance of generalised Reynolds ideals under derived equivalencesSep 24 2005Mar 29 2006For any algebraically closed field $k$ of positive characteristic $p$ and any non negative integer $n$ K\"ulshammer defined ideals $T\_nA^\perp$ of the centre of a symmetric $k$-algebra $A$. We show that for derived equivalent algebras $A$ and $B$ there ... More
Finite-state Strategies in Delay GamesSep 07 2017What is a finite-state strategy in a delay game? We answer this surprisingly non-trivial question and present a very general framework for computing such strategies: they exist for all winning conditions that are recognized by automata with acceptance ... More
Changement de base pour les foncteurs TorMar 14 2003We give in this paper an isomorphism theorem between derived functors over categories of modules.There is a nice class of categories that gives examples in which this theorem applies for a special construction. This leads us to a new interpretation of ... More
Optimal Bounds in Parametric LTL GamesJun 07 2011We consider graph games of infinite duration with winning conditions in parameterized linear temporal logic, where the temporal operators are equipped with variables for time bounds. In model checking such specifications were introduced as "PLTL" by Alur ... More
A feature construction framework based on outlier detection and discriminative pattern miningJul 17 2014No matter the expressive power and sophistication of supervised learning algorithms, their effectiveness is restricted by the features describing the data. This is not a new insight in ML and many methods for feature selection, transformation, and construction ... More
Remarks on a Categorical Definition of Degeneration in Triangulated CategoriesJun 08 2015This work reports on joint research with Manuel Saorin. For an algebra A over an algebraically closed field k the set of A-module structures on k d forms an affine algebraic variety. The general linear group Gl d (k) acts on this variety and isomorphism ... More
The Abelianisation of the real Cremona groupOct 29 2015Apr 15 2016We present the Abelianisation of the birational transformations of $\mathbb{P}_{\mathbb{R}}^2$. Its kernel is equal to the normal subgroup generated by $\mathrm{PGL}_3(\mathbb{R})$, and contains all elements of degree $\leq4$. The description of the quotient ... More
A general track reconstruction scheme and its application to the OPERA drift tubesJun 06 2007A general reconstruction and calibration procedure for tracking and wire position determination of the OPERA drift tubes is presented. The mathematics of the pattern recognition and the track fit are explained.
Electron-Cloud Effects in past and future machines - walk through 50 years of Electron-Cloud studiesAug 06 2013Past electron-cloud (e-cloud) observations, studies and mitigation techniques are quickly reviewed along with some ongoing code developments, the preceding ECLOUD workshops, recent contacts with the spacecraft community, the important role of Francesco ... More
Elementary proof of logarithmic Sobolev inequalities for Gaussian convolutions on $\mathbb{R}$Dec 03 2014In a 2013 paper, the author showed that the convolution of a compactly supported measure on the real line with a Gaussian measure satisfies a logarithmic Sobolev inequality (LSI). In a 2014 paper, the author gave bounds for the optimal constants in these ... More
On harmonic representation of meansOct 11 2013We characterize continuous, symmetric and homogeneous means $M$ that can be represented in the form \begin{equation*} \frac{1}{M(x,y)}=\int_0^1 \frac{dt}{N\left(\tfrac{x+y}{2}-t\tfrac{x-y}{2},\tfrac{x+y}{2}+t\tfrac{x-y}{2}\right)}. \end{equation*} New ... More
Multivariate Stirling Polynomials of the first and second kindNov 20 2013Jul 21 2015Two doubly indexed families of homogeneous and isobaric polynomials in several indeterminates are considered: the (partial) exponential Bell polynomials $B_{n,k}$ and a new family $S_{n,k}$ such that $X_1^{-(2n-1)}S_{n,k}$ and $B_{n,k}$ obey an inversion ... More
10 Years of wire excitation experiments in the CERN SPSOct 14 2014This paper reviews the set-up, experimental studies, and beam observations with one or two prototype long-range beam-beam 'wire' compensators in the CERN SPS from 2002 to 2012.
Dynamical T-matrix theory for high-density excitons in coupled quantum wellsFeb 25 2006Excitons in coupled quantum wells open the possibility to reach high densities close to equilibrium. In a recent experiment employing a lateral trap potential, a blue shift and a broadening of the exciton emission line has been seen (Snoke, SSC 134). ... More
Status of the OPERA ExperimentApr 12 2006In this article the physics motivation and the detector design of the OPERA experiment will be reviewed. The construction status of the detector, which will be situated in the CNGS beam from CERN to the Gran Sasso laboratory, will be reported. A survey ... More
A Noether-Deuring theorem for derived categoriesDec 15 2011Jan 13 2012We prove a Noether-Deuring theorem for the derived category of bounded complexes of modules over a Noetherian algebra.
The Abelianisation of the real Cremona groupOct 29 2015Jun 12 2017We present the abelianisation of the birational transformations of the real projective plane.
Games with Costs and DelaysJan 09 2017Apr 20 2017We demonstrate the usefulness of adding delay to infinite games with quantitative winning conditions. In a delay game, one of the players may delay her moves to obtain a lookahead on her opponent's moves. We show that determining the winner of delay games ... More
Parameterized Linear Temporal Logics Meet Costs: Still not Costlier than LTLSep 24 2015We continue the investigation of parameterized extensions of Linear Temporal Logic (LTL) that retain the attractive algorithmic properties of LTL: a polynomial space model checking algorithm and a doubly-exponential time algorithm for solving games. Alur ... More
Fine Hochschild invariants of derived categories for symmetric algebrasAug 29 2006Let $A$ be a symmetric $k$-algebra over a perfect field $k$. K\"ulshammer defined for any integer $n$ a mapping $\zeta\_n$ on the degree 0 Hochschild cohomology and a mapping $\kappa\_n$ on the degree 0 Hochschild homology of $A$ as adjoint mappings of ... More
Külshammer ideals of algebras of quaternion typeMay 25 2016May 27 2016For a symmetric algebra A over a field K of characteristic p \textgreater{} 0 K{\"u}lshammer constructed a descending sequence of ideals of the centre of A. If K is perfect this sequence was shown to be an invariant under derived equivalence and for algebraically ... More
Hochschild homology invariants of Külshammer type of derived categoriesMay 14 2010For a perfect field $k$ of characteristic $p>0$ and for a finite dimensional symmetric $k$-algebra $A$ K\"ulshammer studied a sequence of ideals of the centre of $A$ using the $p$-power map on degree 0 Hochschild homology. In joint work with Bessenrodt ... More
Simple transitive $2$-representations of some $2$-categories of projective functorsMay 02 2017We show that every simple transitive $2$-representation of the $2$-category of projective functors for a certain quotient of the quadratic dual of the preprojective algebra associated with a tree is equivalent to a cell $2$-representation.
Unbounded Lookahead in WMSO+U GamesSep 24 2015Jan 26 2016Delay games are two-player games of infinite duration in which one player may delay her moves to obtain a lookahead on her opponent's moves. We consider delay games with winning conditions expressed in weak monadic second order logic with the unbounding ... More
From Monolith to Microservices: A Classification of Refactoring ApproachesJul 26 2018Jan 24 2019While the recently emerged Microservices architectural style is widely discussed in literature, it is difficult to find clear guidance on the process of refactoring legacy applications. The importance of the topic is underpinned by high costs and effort ... More
Sets of LengthsSep 24 2015Aug 10 2016Oftentimes the elements of a ring or semigroup $H$ can be written as finite products of irreducible elements, say $a=u_1 \cdot \ldots \cdot u_k = v_1 \cdot \ldots \cdot v_{\ell}$, where the number of irreducible factors is distinct. The set $\mathsf L ... More
The square lattice Ising model on the rectangle I: Finite systemsSep 07 2016Oct 07 2016The partition function of the square lattice Ising model on the rectangle is calculated exactly for arbitrary system size $L\times M$ and temperature. We start with the dimer method of Kasteleyn, McCoy & Wu, construct a highly symmetric block transfer ... More
Non-equilibrium phase transition in an exactly solvable driven Ising model with frictionSep 02 2009Nov 04 2009A driven Ising model with friction due to magnetic correlations has recently been proposed by Kadau et al. (Phys. Rev. Lett. 101, 137205 (2008)). The non-equilibrium phase transition present in this system is investigated in detail using analytical methods ... More
Neutrino Counter Nuclear WeaponMay 26 2008Jun 25 2013Radiations produced by neutrino-antineutrino annihilation at the Z0 pole can be used to heat up the primary stage of a thermonuclear warhead and can in principle detonate the device remotely. Neutrino-antineutrino annihilation can also be used as a tactical ... More
On the Symmetry of Universal Finite-Size Scaling Functions in Anisotropic SystemsFeb 08 2002In this work a symmetry of universal finite-size scaling functions under a certain anisotropic scale transformation is postulated. This transformation connects the properties of a finite two-dimensional system at criticality with generalized aspect ratio ... More
The dynamics of H-bonds of the hydration shells of ions, ATPase and NE-activated adenylyl cyclase on the coupling of energy and signal transductionJul 17 2012Glycerol titration distinguished from free water the local hydration shell involved in ATPase transition from active to inactive, with cooperativity for water n=16. Rat brain cortex: NE-stimulated and its basal AC in the absence of free Mg2+, allows a ... More
Life and Quantum Biology, an Interdisciplinary ApproachSep 12 2011Jul 26 2016The rapidly increasing interest in the quantum properties of living matter stimulates a discussion of the fundamental properties of life as well as quantum mechanics. In this discussion often concepts are used that originate in philosophy and ask for ... More
The coupling of thermodynamics with the organizational water-protein intra-dynamics driven by the H-bonds dissipative potential of cluster waterMar 27 2013The Red cell-Hb-CSF functions as a sensor adapting response to Hb heterotropic equilibriums. At the lungs O2 and Mg2+, each one increasing affinity for the other stabilize the relax (R) form [(O2)4Hb(Mg)2].(H2O)R. At tissue level, the inclusion of H+ ... More
The Thermal Pulses of Very-Low-Mass StarsMar 26 2013Very-low-mass stars can develop secularly unstable hydrogen-burning shells late in their life. Since the thermal pulses that go along are driven at the bottoms of very shallow envelopes, the stars' luminosities and effective temperatures react strongly ... More
Reviving old, almost lost knowledge on T and K matrix poles and a link to the contemporary QCD spectrumFeb 14 2012The old knowledge about interrelation among T-matrix, K-matrix and bare poles is summarized and put into modern perspective.
Characterization of the norepinephrine-activation of adenylate cyclase suggests a role in memory affirmation pathways. Overexposure to epinephrine inactivates adenylate-cyclase,a causal pathway for stress-pathologiesDec 15 2010Incubation with noradrenaline (norepinephrine) of isolated membranes of rat's brain corpus striatum and cortex, showed that ionic-magnesium (Mg2+) is required for the neurotransmitter activatory response of Adenylate Cyclase [ATP pyrophosphate-lyase (cyclizing), ... More
The theorem that was none - II. The profound 70sDec 31 2018This second pedagogical installment on the history of the Vogt-Russell theorem focuses on research in the 1970s on the existence and uniqueness of star models. An appendix presents stellar evolution models, computed with the MESA code, in different approximations ... More
Mitigating performance limitations of single beam-pipe circular e+e- collidersJun 02 2015Renewed interest in circular e+e- colliders has spurred designs of single beam-pipe machines, like the CEPC in China, and double beam pipe ones, such as the FCC-ee effort at CERN. Single beam-pipe designs profit from lower costs but are limited by the ... More
A Multi-level Blocking Distinct Degree Factorization AlgorithmOct 24 2007We give a new algorithm for performing the distinct-degree factorization of a polynomial P(x) over GF(2), using a multi-level blocking strategy. The coarsest level of blocking replaces GCD computations by multiplications, as suggested by Pollard (1975), ... More
On Jordan type bounds for finite groups of diffeomorphisms of 3-manifolds and Euclidean spacesFeb 07 2014By a classical result of Jordan, each finite subgroup G of a complex linear group GL_n(C) has an abelian subgroup whose index in G is bounded by a constant depending only on n. We consider the problem if this remains true for finite subgroups G of the ... More
Non-circular semiconductor nanorings of type I and II: Emission kinetics in the exciton Aharonov-Bohm effectSep 17 2007Transition energies and oscillator strengths of excitons in dependence on magnetic field are investigated in type I and II semiconductor nanorings. A slight deviation from circular (concentric) shape of the type II nanoring gives a better observability ... More
Near-field spectra of quantum well excitons with non-Markovian phonon scatteringDec 20 2005Apr 03 2006The excitonic absorption spectrum for a disordered quantum well in presence of exciton-acoustic phonon interaction is treated beyond the Markov approximation. Realistic disorder exciton states are taken from a microscopic simulation, and the deformation ... More
Coherent potential approximation for spatially correlated disorderApr 25 2009Oct 15 2009The coherent potential approximation (CPA) is extended to describe satisfactorily the motion of particles in a random potential which is spatially correlated and smoothly varying. In contrast to existing cluster-CPA methods, the present scheme preserves ... More
Electron-Phonon Interaction in Embedded Semiconductor NanostructuresOct 15 2006The modification of acoustic phonons in semiconductor nanostructures embedded in a host crystal is investigated including corrections due to strain within continuum elasticity theory. Effective elastic constants are calculated employing {\em ab initio} ... More
Optical absorption in quantum dots: Coupling to longitudinal optical phonons treated exactlyJun 16 2005Jan 31 2006Optical transitions in a semiconductor quantum dot are theoretically investigated, with emphasis on the coupling to longitudinal optical phonons, and including excitonic effects. When limiting to a finite number of $m$ electron and $n$ hole levels in ... More
Decentralization as Organizing Principle of Emergent Urban StructuresMar 07 2002With a view to the ongoing Bologna project (www.arXiv.org/pdf/nlin.AO/0109025) general organizing principles of emergent structures in social systems are being discussed with a view to the meaning of decentralization. It is proposed to introduce decentralization ... More
Particles held by springs in a linear shear flow exhibit oscillatory motionApr 26 2006Jun 01 2006The dynamics of small spheres, which are held by linear springs in a low Reynolds number shear flow at neighboring locations is investigated. The flow elongates the beads and the interplay of the shear gradient with the nonlinear behavior of the hydrodynamic ... More
On minimal actions of finite simple groups on homology spheres and Euclidean spacesDec 05 2008Sep 03 2010We consider the following problem: for which classes of finite groups, and in particular finite simple groups, does the minimal dimension of a faithful, smooth action on a homology sphere coincide with the minimal dimension of a faithful, linear action ... More
Evaluation of the importance of spin-orbit couplings in the nonadiabatic quantum dynamics with quantum fidelity and with its efficient "on-the-fly" ab initio semiclassical approximationJun 27 2012We propose to measure the importance of spin-orbit couplings (SOCs) in the nonadiabatic molecular quantum dynamics rigorously with quantum fidelity. To make the criterion practical, quantum fidelity is estimated efficiently with the multiple-surface dephasing ... More
Path integral evaluation of equilibrium isotope effectsMay 11 2009A general and rigorous methodology to compute the quantum equilibrium isotope effect is described. Unlike standard approaches, ours does not assume separability of rotational and vibrational motions and does not make the harmonic approximation for vibrations ... More
Benchmarking electron-cloud simulations and pressure measurements at the LHCJun 24 2013During the beam commissioning of the Large Hadron Collider (LHC) with 150, 75, 50 and 25-ns bunch spacing, important electron-cloud effects, like pressure rise, cryogenic heat load, beam instabilities or emittance growth, were observed. A method has been ... More
Random Matrices with Log-Range Correlations, and Log-Sobolev InequalitiesMay 11 2014Dec 06 2016Let $X_N$ be a symmetric $N\times N$ random matrix whose $\sqrt{N}$-scaled centered entries are uniformly square integrable. We prove that if the entries of $X_N$ can be partitioned into independent subsets each of size $o(\log N)$, then the empirical ... More
On minimal actions of linear fractional and finite simple groups on homology spheresMay 17 2006Sep 03 2010This paper has been withdrawn since it is superated by the latest version of arXiv:0812.1139 (this is the version which will appear in Rend. Circ. Mat. Palermo; it is a strengthening and elaboration of a paper published in Math. Proc. Camb. Phil. Soc. ... More
On finite simple and nonsolvable groups acting on homology 4-spheresJul 08 2005The only finite nonabelian simple group acting on a homology 3-sphere - necessarily non-freely - is the dodecahedral group $\Bbb A_5 \cong {\rm PSL}(2,5)$ (in analogy, the only finite perfect group acting freely on a homology 3-sphere is the binary dodecahedral ... More
The First-Order Logic of HyperpropertiesOct 14 2016Jan 09 2017We investigate the logical foundations of hyperproperties. Hyperproperties generalize trace properties, which are sets of traces, to sets of sets of traces. The most prominent application of hyperproperties is information flow security: information flow ... More
Visibly Linear Dynamic LogicDec 16 2015May 17 2017We introduce Visibly Linear Dynamic Logic (VLDL), which extends Linear Temporal Logic (LTL) by temporal operators that are guarded by visibly pushdown languages over finite words. In VLDL one can, e.g., express that a function resets a variable to its ... More
A tutorial on recursive models for analyzing and predicting path choice behaviorMay 02 2019The problem at the heart of this tutorial consists in modeling the path choice behavior of network users. This problem has extensively been studied in transportation science and econometrics, where it is known as the route choice problem. In this literature, ... More
Proceedings Ninth International Symposium on Games, Automata, Logics, and Formal VerificationSep 07 2018This volume contains the proceedings of the Ninth International Symposium on Games, Automata, Logic and Formal Verification (GandALF 2018). The symposium took place in Saarbr\"ucken, Germany, from the 26th to the 28th of September 2018. The GandALF symposium ... More
Representation-tame algebras need not be homologically tameSep 26 2015We show that, also within the class of representation-tame finite dimensional algebras $\Lambda$, the big left finitistic dimension of $\Lambda$ may be strictly larger than the little. In fact, the discrepancies $Findim \Lambda - findim \Lambda$ need ... More
Top-stable degenerations of finite dimensional representations IJul 10 2014Given a finite dimensional representation $M$ of a finite dimensional algebra, two hierarchies of degenerations of $M$ are analyzed in the context of their natural orders: the poset of those degenerations of $M$ which share the top $M/JM$ with $M$ - here ... More
On topological actions of finite, non-standard groups on spheresFeb 15 2016Jul 19 2016The standard actions of finite groups on spheres S^d are linear actions, i.e. by finite subgroups of the orthogonal group O(d+1). We prove that, in each dimension d>5, there is a finite group G which admits a faithful, topological action on a sphere S^d ... More
Analysis of the exciton-exciton interaction in semiconductor quantum wellsFeb 22 2008Jul 23 2008The exciton-exciton interaction is investigated for quasi-two-dimensional quantum structures. A bosonization scheme is applied including the full spin structure. For generating the effective interaction potentials, the Hartree-Fock and Heitler-London ... More
On Morita theory for self-dual modulesMar 25 2008Let $G$ be a finite group and let $k$ be a field of characteristic $p$. It is known that a $kG$-module $V$ carries a non-degenerate $G$-invariant bilinear form $b$ if and only if $V$ is self-dual. We show that whenever a Morita bimodule $M$ which induces ... More
Visibly Linear Dynamic LogicDec 16 2015We introduce Visibly Linear Dynamic Logic (VLDL), which is an extension of Linear Dynamic Logic (LDL) with temporal operators that are guarded by nondeterministic visibly pushdown automata. We prove that VLDL describes exactly the visibly pushdown languages ... More
How Much Lookahead is Needed to Win Infinite Games?Dec 11 2014Aug 25 2016Delay games are two-player games of infinite duration in which one player may delay her moves to obtain a lookahead on her opponent's moves. For omega-regular winning conditions, it is known that such games can be solved in doubly-exponential time and ... More
Easy to Win, Hard to Master: Optimal Strategies in Parity Games with CostsApr 19 2016The winning condition of a parity game with costs requires an arbitrary, but fixed bound on the distance between occurrences of odd colors and the next occurrence of a larger even one. Such games quantitatively extend parity games while retaining most ... More
The First-Order Logic of HyperpropertiesOct 14 2016We investigate the logical foundations of hyperproperties. Hyperproperties generalize trace properties, which are sets of traces, to sets of sets of traces. The most prominent application of hyperproperties is information flow security: information flow ... More
Auslander-Reiten conjecture for symmetric algebras of polynomial growthMay 07 2010This paper studies self-injective algebras of polynomial growth. We prove that the derived equivalence classification of weakly symmetric algebras of domestic type coincides with the classification up to stable equivalences (of Morita type). As for weakly ... More
Classifying tame blocks and related algebras up to stable equivalences of Morita typeMay 03 2010We contribute to the classification of finite dimensional algebras under stable equivalence of Morita type. More precisely we give a classification of the class of Erdmann's algebras of dihedral, semi-dihedral and quaternion type and obtain as byproduct ... More
Proton Colliders at the Energy FrontierMar 26 2018Since the CERN ISR, hadron colliders have defined the energy frontier. Noteworthy are the conversion of the Super Proton Synchrotron (SPS) into a proton-antiproton collider, the Tevatron collider, as well as the abandoned SSC in the United States. Hadron ... More
On finite groups acting on homology 4-spheres and finite subgroups of SO(5)Jan 22 2010Apr 13 2010We show that a finite group which admits a faithful, smooth, orientation-preserving action on a homology 4-sphere, and in particular on the 4-sphere, is isomorphic to a subgroup of the orthogonal group SO(5), by explicitly determining the various groups ... More
A note on actions of the symplectic group Sp(2g,Z) on homology spheresMar 17 2009The symplectic group Sp(2g,Z) is a subgroup of the linear group SL(2g,Z) and admits a faithful action on the sphere S^(2g-1), induced from its linear action on Euclidean space R^(2g). Generalizing corresponding results for linear groups, we show that, ... More
What are Strategies in Delay Games? Borel Determinacy for Games with LookaheadApr 10 2015We investigate determinacy of delay games with Borel winning conditions, infinite-duration two-player games in which one player may delay her moves to obtain a lookahead on her opponent's moves. First, we prove determinacy of such games with respect to ... More
Parity and Streett Games with CostsJul 03 2012Jun 24 2014We consider two-player games played on finite graphs equipped with costs on edges and introduce two winning conditions, cost-parity and cost-Streett, which require bounds on the cost between requests and their responses. Both conditions generalize the ... More
Parametric Linear Dynamic LogicAug 26 2014We introduce Parametric Linear Dynamic Logic (PLDL), which extends Linear Dynamic Logic (LDL) by temporal operators equipped with parameters that bound their scope. LDL was proposed as an extension of Linear Temporal Logic (LTL) that is able to express ... More
A High Luminosity e+e- Collider in the LHC tunnel to study the Higgs BosonDec 12 2011Feb 15 2012We consider the possibility of a 120x120 GeV e+e- ring collider in the LHC tunnel. A luminosity of 10^34/cm2/s can be obtained with a luminosity life time of a few minutes. A high operation efficiency would require two machines: a low emittance collider ... More
Memory and correlation effects in the exciton-phonon kineticsApr 05 2006Memory and correlation effects in the interband absorption from quantum wells due to exciton-phonon dynamics are investigated. They are traced back to the frequency dependence and matrix character of the self energy arising in a 2nd Born theory. It is ... More
Recent Conceptual Consequences of Loop Quantum Gravity. Part III: A Postscript On TimeAug 15 2001With a view to the results discussed in the first two parts of this paper, the concept of time is revisited oncemore and chosen as an example in order to demonstrate the meaning of fundamental in both physical and philosophical terms. It is shown that ... More
Beyond the Physics of Logic: Aspects of Transcendental Materialism or URAM in a Modern ViewMay 28 2001It has been shown at other occasions that recent results of modern physics can be used to shed some more light onto the foundations of the world, provided the actual task of philosophy is being re-interpreted in terms of a theory which is following up ... More
Coherent Control for a Two-level System Coupled to PhononsJul 15 1998Sep 23 1998The interband polarizations induced by two phase-locked pulses in a semiconductor show strong interference effects depending on the time tau_1 separating the pulses. The four-wave mixing signal diffracted from a third pulse delayed by tau is coherently ... More
An axiomatic approach for degenerations in triangulated categoriesJun 09 2015We generalise Yoshino's definition of a degeneration of two Cohen Macaulay modules to a definition of degeneration between two objects in a triangulated category. We derive some natural properties for the triangulated category and the degeneration under ... More
Evaluation of the nondiabaticity of quantum molecular dynamics with the dephasing representation of quantum fidelityApr 01 2010May 20 2010We propose an approximate method for evaluating the importance of non-Born-Oppenheimer effects on the quantum dynamics of nuclei. The method uses a generalization of the dephasing representation (DR) of quantum fidelity to several diabatic potential energy ... More
Traveling ion channel density waves affected by a conservation lawFeb 15 2006Apr 07 2006A model of mobile, charged ion channels embedded in a biomembrane is investigated. The ion channels fluctuate between an opened and a closed state according to a simple two-state reaction scheme whereas the total number of ion channels is a conserved ... More
Purity, algebraic compactness, direct sum decompositions, and representation typeJul 09 2014This survey article is devoted to the notions of purity, algebraic and $\Sigma$-algebraic compactness, direct sum decompositions, and representation type in the category of modules over a ring. It begins with basic definitions, a brief history, and a ... More
A classification of maximally symmetric surfaces in the 3-dimensional torusApr 07 2018If a finite group of orientation-preserving diffeomorphisms of the 3-dimensional torus leaves invariant an oriented, closed, embedded surface of genus g>1 and preserves the orientation of the surface, then its order is bounded from above by 12(g-1). In ... More
On finite simple groups acting on homology spheres with small fixed point setsMay 28 2014A finite nonabelian simple group does not admit a free action on a homology sphere, and the only finite simple group which acts on a homology sphere with at most 0-dimensional fixed point sets ("pseudofree action") is the alternating group A_5 acting ... More
Verdier quotients of homotopy categoriesNov 15 2017May 29 2018We study Verdier quotients of diverse homotopy categories of a full additive subcategory $\mathcal E$ of an abelian category. In particular, we consider the categories $K^{x,y}({\mathcal E})$ for $x\in\{\infty, +,-,b\}$, and $y\in\{\emptyset,b,+,-,\infty\}$ ... More
On finite groups acting on a connected sum of 3-manifolds S^2 \times S^1Feb 24 2012Feb 09 2014Let H_g denote the closed 3-manifold obtained as the connected sum of g copies of S^2 times S^1, with free fundamental group of rank g. We prove that, for a finite group G acting on H_g which induces a faithful action on the fundamental group, there is ... More