Browsing 1  Oberwolfach Preprints (OWP) by Title
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Simple vector bundles on plane degenerations of an elliptic curve
[OWP200920] (Mathematisches Forschungsinstitut Oberwolfach, 20090313)In 1957 Atiyah classified simple and indecomposable vector bundles on an elliptic curve. In this article we generalize his classification by describing the simple vector bundles on all reduced plane cubic curves. Our main ... 
The Simplicial Complex of Brauer Pairs of a Finite Reductive Group
[OWP202312] (Mathematisches Forschungsinstitut Oberwolfach, 20230717)In this paper we study the simplicial complex induced by the poset of Brauer pairs ordered by inclusion for the family of finite reductive groups. In the defining characteristic case the homotopy type of this simplicial ... 
Simulation of Multibody Systems with Servo Constraints through Optimal Control
[OWP201518] (Mathematisches Forschungsinstitut Oberwolfach, 2015)We consider mechanical systems where the dynamics are partially constrained to prescribed trajectories. An example for such a system is a building crane with a load and the requirement that the load moves on a certain path. ... 
Singer quadrangles
[OWP200907] (Mathematisches Forschungsinstitut Oberwolfach, 20090301) 
Singularities and Bifurcations of Pseudospherical Surfaces
[OWP202008] (Mathematisches Forschungsinstitut Oberwolfach, 20200317)We study singularities and bifurcations of constant negative curvature surfaces in Euclidean 3space via their association with Lorentzian harmonic maps. This preprint presents the basic results on this, the full proofs ... 
Slowly oscillating wave solutions of a single species reactiondiffusion equation with delay
[OWP200712] (Mathematisches Forschungsinstitut Oberwolfach, 20070328)We study positive bounded wave solutions $u(t, x) = \phi(\nu \cdot x+ct)$, $\phi(\infty)=0$, of equation $u_t(t, x)=\delta u(t,x)−u(t,x) +g(u(t−h,x))$, $x \in \mathbb{R}^m$(*). It is supposed that Eq. (∗) has exactly two ... 
Solid extensions of the Cesàro operator on the Hardy space H2(D)
[OWP201311] (Mathematisches Forschungsinstitut Oberwolfach, 20130423)We introduce and study the largest Banach space of analytic functions on the unit disc which is solid for the coefficientwise order and to which the classical Ces`aro operator $\mathcal{C}:H^2 \to H^2$ can be continuously ... 
Some Combinatorial Identities Related to Commuting Varieties and Hilbert Schemes
[OWP201102] (Mathematisches Forschungsinstitut Oberwolfach, 2011)In this article we explore some of the combinatorial consequences of recent results relating the isospectral commuting variety and the Hilbert scheme of points in the plane. 
Some Homological Properties of Borel Type Ideals
[OWP202203] (Mathematisches Forschungsinstitut Oberwolfach, 20220201)We study ideals of Borel type, including $k$Borel ideals and $t$spread Veronese ideals. We determine their free resolutions and their homological shift ideals. The multiplicity and the analytic spread of equigenerated ... 
Some Results on Reducibility of Parabolic Induction for Classical Groups
[OWP201709] (Mathematisches Forschungsinstitut Oberwolfach, 20170330)Given a (complex, smooth) irreducible representation $\pi$ of the general linear group over a nonarchimedean local field and an irreducible supercuspidal representation $\sigma$ of a classical group, we show that ... 
Some Results Related to Schiffer's Problem
[OWP201818] (Mathematisches Forschungsinstitut Oberwolfach, 20180816)We consider the following semilinear overdetermined problem on a two dimensional bounded or unbounded domain $\Omega$ with analytic boundary $\partial\Omega$ having at least one bounded connected component \begin{eqnarray*} ... 
SpaceTime Euler Discretization Schemes for the Stochastic 2D NavierStokes Equations
[OWP202012] (Mathematisches Forschungsinstitut Oberwolfach, 20200506)We prove that the implicit time Euler scheme coupled with finite elements space discretization for the 2D NavierStokes equations on the torus subject to a random perturbation converges in $L^2(\Omega)$, and describe the ... 
SpatialSkin Effect for a Spectral Problem with "Slightly Heavy" Concentrated Masses in a Thick Cascade Junction
[OWP201210] (Mathematisches Forschungsinstitut Oberwolfach, 20120703)The asymptotic behavior (as $\varepsilon \to 0$) of eigenvalues and eigenfunctions of a boundary value problem for the Laplace operator in a thick cascade junction with concentrated masses is studied. This cascade junction ... 
Spectral Continuity for Aperiodic Quantum Systems II. Periodic Approximations in 1D
[OWP201827] (Mathematisches Forschungsinstitut Oberwolfach, 20181217)The existence and construction of periodic approximations with convergent spectra is crucial in solid state physics for the spectral study of corresponding Schrödinger operators. In a forthcoming work [9] this task was ... 
Spectral Sequences in Combinatorial Geometry: Cheeses, Inscribed Sets, and BorsukUlam Type Theorems
[OWP201008] (Mathematisches Forschungsinstitut Oberwolfach, 20100312)Algebraic topological methods are especially suited to determining the nonexistence of continuous mappings satisfying certain properties. In combinatorial problems it is sometimes possible to define a mapping from a space ... 
Spectral triples and finite summability on CuntzKrieger algebras
[OWP201403] (Mathematisches Forschungsinstitut Oberwolfach, 20140513)We produce a variety of odd bounded Fredholm modules and odd spectral triples on CuntzKrieger algebras by means of realizing these algebras as "the algebra of functions on a noncommutative space" coming from a sub shift ... 
Spherical Actions on Flag Varieties
[OWP201404] (Mathematisches Forschungsinstitut Oberwolfach, 20140425)For every finitedimensional vector space $V$ and every $V$ flag variety $X$ we list all connected reductive subgroups in $GL(V)$ acting spherically on $X$. 
Spherical ArcLength as a Global Conformal Parameter for Analytic Curves in the Riemann Sphere
[OWP201621] (Mathematisches Forschungsinstitut Oberwolfach, 20161111)We prove that for every analytic curve in the complex plane $\mathbb{C}$, Euclidean and spherical arclengths are global conformal parameters. We also prove that for any analytic curve in the hyperbolic plane, hyperbolic ... 
Splitting Necklaces, with Constraints
[OWP202003] (Mathematisches Forschungsinstitut Oberwolfach, 20200211)We prove several versions of Alon's "necklacesplitting theorem", subject to additional constraints, as illustrated by the following results. (1) The "almost equicardinal necklacesplitting theorem" claims that, without ... 
Square wave periodic solutions of a differential delay equation
[OWP201409] (Mathematisches Forschungsinstitut Oberwolfach, 20140513)We prove the existence of periodic solutions of the differential delay equation $\varepsilon\dot{x}(t) + x(t)= f(x(t1)), \varepsilon>0$ under the assumptions that the continuous nonlinearity $f(x)$ satisfies the negative ...