Consistency properties of concurrent computations, e.g., sequential consistency, linearizability, or eventual consistency, are essential for devising correct concurrent algorithms. In this paper, we present a logical formalization of such consistency properties that is based on a standard logic of knowledge. Our formalization provides a declarative perspective on what is imposed by consistency requirements and provides some interesting unifying insight on differently looking properties.

Klaus v. Gleissenthall Andrey Rybalchenko

In the SIGGRAPH 2014 paper [SvTSH14] an approach for animating deformable objects using sparse spacetime constraints is introduced. This report contains the proofs of two theorems presented in the paper.

Christian Schulz Christoph von Tycowicz Hans-Peter Seidel Klaus Hildebrandt

We calculate the S-invariant of Connes for the von Neumann algebra factors arising from KMS-weights of a generalized gauge action on a simple graph C*-algebra when the associated measure on the infinite path space of the graph is dissipative under the action of the shift.

Klaus Thomsen

The short Communication based on results of notes: Andre Geim "When lost in a multiverse" (Nat. Phys. 13, 1142 (2017)) and Klaus von Klitzing "Metrology in 2019" (Nat. Phys. 13, 198 (2017))

I. A. Weinstein

We investigate the formation of fullerene-like structures from hot Carbon gas using classical molecular dynamics, employing Brenner's potential. In particular we examine the influence of different annealing strategies on fullerene yield, which is characterized by the distribution of coordination numbers and polygon numbers. It will be shown that the fullerene yield strongly depends on the annealing strategy. Furthermore, we observe a close relation between polygon formation and the number of atoms surrounded by three atoms.

Klaus Lichtenegger Wolfgang von der Linden

The Kruskal-Segur approach to selection theory in diffusion-limited or Laplacian growth is extended via combination with the Zauderer decomposition scheme. This way nonlinear bulk equations become tractable. To demonstrate the method, we apply it to two-dimensional crystal growth in a potential flow. We omit the simplifying approximations used in a preliminary calculation for the same system [T. Fischaleck, K. Kassner, EPL 81, 54004 (2008)], thus exhibiting the capability of the method to extend mathematical rigor to more complex problems than hitherto accessible.

Martin von Kurnatowski Thomas Grillenbeck Klaus Kassner

The paper contains a description of the KMS weights for the one-parameter action on the reduced C*-algebra of a second countable locally compact Hausdorff etale groupoid, arising from a continuous real valued homomorphism satisfying two conditions. The results are subsequently applied to identify the KMS weights for the gauge action on a simple graph algebra. The von Neumann algebra generated by the GNS-representation of an extremal KMS weight is a factor, and tools are developed to determine its type. The paper concludes with three examples to illustrate the results.

Klaus Thomsen

Using a nonlinear Schr\"{o}dinger equation for the wave function of all systems, continuous transitions between quantum and classical motions are demonstrated for (i) the double-slit set up, (ii) the 2D harmonic oscillator and (iii) the hydrogen-like atom, all of which are of empirical interest.

Partha Ghose Klaus von Bloh

The Haag-Kastler net of local von Neumann algebras is constructed in the ultraviolet finite regime of the sine-Gordon model, and its equivalence with the massive Thirring model is proved. In contrast to other authors, we do not add an auxiliary mass term, and we work completely in Lorentzian signature. The construction is based on the functional formalism for perturbative Algebraic Quantum Field Theory together with estimates originally derived within Constructive Quantum Field Theory and adapted to Lorentzian signature. The paper extends previous work by two of us.

Dorothea Bahns Klaus Fredenhagen Kasia Rejzner

We revisit the Krein-von Neumann extension in the case where the underlying symmetric operator is strictly positive and apply this to derive the explicit form of the Krein-von Neumann extension for singular, general (i.e., three-coefficient) Sturm-Liouville operators on arbitrary intervals. In particular, the boundary conditions for the Krein-von Neumann extension of the strictly positive minimal Sturm-Liouville operator are explicitly expressed in terms of generalized boundary values adapted to the (possible) singularity structure of the coefficients near an interval endpoint.

Guglielmo Fucci Fritz Gesztesy Klaus Kirsten Lance L. Littlejohn Roger Nichols Jonathan Stanfill