Results 21 to 30 of about 44 (44)
Scattering theory for difference equations with operator coefficients
Abstract We investigate a class of second‐order difference equations featuring operator‐valued coefficients with the aim of approaching problems of stationary scattering theory. We focus on various compact perturbations of the discrete Laplacian given in a Hilbert space of bi‐infinite square‐summable sequences with entries from a fixed Hilbert space ...
David Sher +3 more
wiley +1 more source
Abstract We count and give a parametrization of connected components in the space of flags transverse to a given transverse pair in every flag varieties of SO0(p,q)$\operatorname{SO}_0(p,q)$. We compute the effect the involution of the unipotent radical has on those components and, using methods of Dey–Greenberg–Riestenberg, we show that for certain ...
Clarence Kineider, Roméo Troubat
wiley +1 more source
Critically fixed Thurston maps: classification, recognition, and twisting
Abstract An orientation‐preserving branched covering map f:S2→S2$f\colon S^2\rightarrow S^2$ is called a critically fixed Thurston map if f$f$ fixes each of its critical points. It was recently shown that there is an explicit one‐to‐one correspondence between Möbius conjugacy classes of critically fixed rational maps and isomorphism classes of planar ...
Mikhail Hlushchanka, Nikolai Prochorov
wiley +1 more source
Abstract In this paper a fixed‐point solver for mappings from a simplex into itself that is gradient‐free, global and requires d$d$ function evaluations for halving the error is presented, where d$d$ is the dimension. It is based on topological arguments and uses the constructive proof of the Mazurkewicz–Knaster–Kuratowski lemma when used as part of ...
Thilo Moshagen
wiley +1 more source
New upper bound for lattice covering by spheres
Abstract We show that there exists a lattice covering of Rn$\mathbb {R}^n$ by Euclidean spheres of equal radius with density O(nlnβn)$O\big (n \ln ^{\beta } n \big)$ as n→∞$n\rightarrow \infty$, where β≔12log28πe33=1.85837….$$\begin{align*} \beta \coloneqq \frac{1}{2} \log _2 {\left(\frac{8 \pi \mathrm{e}}{3\sqrt 3}\right)}=1.85837\,\ldots . \end{align*
Jun Gao +3 more
wiley +1 more source
The shift‐homological spectrum and parametrising kernels of rank functions
Abstract For any compactly generated triangulated category, we introduce two topological spaces, the shift spectrum and the shift‐homological spectrum. We use them to parametrise a family of thick subcategories of the compact objects, which we call radical.
Isaac Bird +2 more
wiley +1 more source
Mirror symmetry, Laurent inversion, and the classification of Q$\mathbb {Q}$‐Fano threefolds
Abstract We describe recent progress in a program to understand the classification of three‐dimensional Fano varieties with Q$\mathbb {Q}$‐factorial terminal singularities using mirror symmetry. As part of this we give an improved and more conceptual understanding of Laurent inversion, a technique that sometimes allows one to construct a Fano variety X$
Tom Coates +2 more
wiley +1 more source
Centrality of star and monotone factorisations
Abstract A factorisation problem in the symmetric group is central if conjugate permutations always have the same number of factorisations. We give the first fully combinatorial proof of the centrality of transitive star factorisations that is valid in all genera, which answers a natural question of Goulden and Jackson from 2009.
Jesse Campion Loth, Amarpreet Rattan
wiley +1 more source
Abstract Motivated by general probability theory, we say that the set S$S$ in Rd$\mathbb {R}^d$ is antipodal of rank k$k$, if for any k+1$k+1$ elements q1,…qk+1∈S$q_1,\ldots q_{k+1}\in S$, there is an affine map from convS$\mathrm{conv}\!\left(S\right)$ to the k$k$‐dimensional simplex Δk$\Delta _k$ that maps q1,…qk+1$q_1,\ldots q_{k+1}$ bijectively ...
Márton Naszódi +2 more
wiley +1 more source
Some of the next articles are maybe not open access.
Bijective Digitized Rigid Motions on Subsets of the Plane
Journal of Mathematical Imaging and Vision, 2017Pascal Romón +2 more
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