Browsing 2022 by Title
Now showing items 9-20 of 20
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Deciding Non-Freeness of Rational Möbius Groups
[OWP-2022-07] (Mathematisches Forschungsinstitut Oberwolfach, 2022-03-22)We explore a new computational approach to a classical problem: certifying non-freeness of (2-generator, parabolic) Möbius subgroups of SL(2, $\mathbb{Q}$). The main tools used are algorithms for Zariski dense groups and ... -
Discretization of Inherent ODEs and the Geometric Integration of DAEs with Symmetries
[OWP-2022-10] (Mathematisches Forschungsinstitut Oberwolfach, 2022-06-08)Discretization methods for differential-algebraic equations (DAEs) are considered that are based on the integration of an associated inherent ordinary differential equation (ODE). This allows to make use of any discretization ... -
Embedding Spaces of Split Links
[OWP-2022-13] (Mathematisches Forschungsinstitut Oberwolfach, 2022-08-01)We study the homotopy type of the space $\mathcal{E}(L)$ of unparametrised embeddings of a split link $L=L_1\sqcup \ldots \sqcup L_n$ in $\mathbb{R}^3$. Inspired by work of Brendle and Hatcher, we introduce a semi-simplicial ... -
Hutchinson's Intervals and Entire Functions from the Laguerre-Pólya Class
[OWP-2022-19] (Mathematisches Forschungsinstitut Oberwolfach, 2022-12-12)We find the intervals $[\alpha, \beta (\alpha)]$ such that if a univariate real polynomial or entire function $f(z) = a_0 + a_1 z + a_2 z^2 + \cdots $ with positive coefficients satisfy the conditions $ \frac{a_{k-1}^2}{ ... -
Local and Global Canonical Forms for Differential-Algebraic Equations with Symmetries
[OWP-2022-05] (Mathematisches Forschungsinstitut Oberwolfach, 2022-02-21)Linear time-varying differential-algebraic equations with symmetries are studied. The structures that we address are self-adjoint and skew-adjoint systems. Local and global canonical forms under congruence are presented ... -
On a Conjecture of Khoroshkin and Tolstoy
[OWP-2022-14] (Mathematisches Forschungsinstitut Oberwolfach, 2022-08-02)We prove a no-go theorem on the factorization of the lower triangular part in the Gaussian decomposition of the Yangian's universal $R$-matrix, yielding a negative answer to a conjecture of Khoroshkin and Tolstoy from ... -
On the Enumeration of Finite $L$-Algebras
[OWP-2022-11] (Mathematisches Forschungsinstitut Oberwolfach, 2022-06-29)We use Constraint Satisfaction Methods to construct and enumerate finite L-algebras up to isomorphism. These objects were recently introduced by Rump and appear in Garside theory, algebraic logic, and the study of the ... -
Quasi-Equilibria and Click Times for a Variant of Muller's Ratchet
[OWP-2022-18] (Mathematisches Forschungsinstitut Oberwolfach, 2022-11-30)Consider a population of $N$ individuals, each of them carrying a type in $\mathbb N_0$. The population evolves according to a Moran dynamics with selection and mutation, where an individual of type $k$ has the same selective ... -
Root Cycles in Coxeter Groups
[OWP-2022-16] (Mathematisches Forschungsinstitut Oberwolfach, 2022-09-15)For an element $w$ of a Coxeter group $W$ there are two important attributes, namely its length, and its expression as a product of disjoint cycles in its action on $\Phi$, the root system of $W$. This paper investigates ... -
Shock-avoiding Slicing Conditions: Tests and Calibrations
[OWP-2022-12] (Mathematisches Forschungsinstitut Oberwolfach, 2022-07-19)While the 1+log slicing condition has been extremely successful in numerous numerical relativity simulations, it is also known to develop "gauge-shocks" in some examples. Alternative "shockavoiding" slicing conditions ... -
Some Homological Properties of Borel Type Ideals
[OWP-2022-03] (Mathematisches Forschungsinstitut Oberwolfach, 2022-02-01)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 ... -
Trivial Source Character Tables of SL2(q)
[OWP-2022-02] (Mathematisches Forschungsinstitut Oberwolfach, 2022-01-28)We compute the trivial source character tables (also called species tables of the trivial source ring) of the infinite family of finite groups SL(2,q) over a large enough field of positive characteristic $\ell$ via ...