Results 61 to 70 of about 2,701,761 (237)

Sparse graph signals – uncertainty principles and recovery

open access: yesGAMM-Mitteilungen, Volume 48, Issue 2, June 2025.
ABSTRACT We study signals that are sparse either on the vertices of a graph or in the graph spectral domain. Recent results on the algebraic properties of random integer matrices as well as on the boundedness of eigenvectors of random matrices imply two types of support size uncertainty principles for graph signals.
Tarek Emmrich   +2 more
wiley   +1 more source

The Picard group in equivariant homotopy theory via stable module categories

open access: yesJournal of Topology, Volume 18, Issue 2, June 2025.
Abstract We develop a mechanism of “isotropy separation for compact objects” that explicitly describes an invertible G$G$‐spectrum through its collection of geometric fixed points and gluing data located in certain variants of the stable module category.
Achim Krause
wiley   +1 more source

Bad Groups [PDF]

open access: yesarXiv, 2017
There is no bad group of Morley rank 2n+1 with an abelian Borel subgroup of Morley rank n. In particular, there is no bad group of Morley rank 3 (O. Fr{\'e}con).
arxiv  

Restart Perturbations for Reversible Markov Chains: Trichotomy and Pre‐Cutoff Equivalence

open access: yesRandom Structures &Algorithms, Volume 66, Issue 3, May 2025.
ABSTRACT Given a reversible Markov chain Pn$$ {P}_n $$ on n$$ n $$ states, and another chain P˜n$$ {\tilde{P}}_n $$ obtained by perturbing each row of Pn$$ {P}_n $$ by at most αn$$ {\alpha}_n $$ in total variation, we study the total variation distance between the two stationary distributions, ‖πn−π˜n‖$$ \left\Vert {\pi}_n-{\tilde{\pi}}_n\right\Vert $$.
Daniel Vial, Vijay Subramanian
wiley   +1 more source

A note on torsion-free abelian groups of finite rank [PDF]

open access: yesProceedings of the American Mathematical Society, 1973
Let G be a torsion-free abelian group of rank n and X= {xl, *. , x,j a maximal set of rationally independent elements in G. It is well known that any g e G can be uniquely written g= oc1xl?+ +x, for some cci, . , ?C72, E Q, the rational numbers. This enables us to define, for any such (G, X), a collection of subgroups of Q and "natural" isomorphisms ...
W. Wickless, C. Vinsonhaler
openaire   +1 more source

Minimal limit key polynomials

open access: yesJournal of the London Mathematical Society, Volume 111, Issue 5, May 2025.
Abstract In this paper, we extend the theory of minimal limit key polynomials of valuations on the polynomial ring K[x]$K[x]$. Minimal key polynomials are useful to describe, for instance, the defect of an extension of valued fields. We use the theory of cuts on ordered abelian groups to show that the previous results on bounded sets of key polynomials
Enric Nart, Josnei Novacoski
wiley   +1 more source

On groups and counter automata [PDF]

open access: yes, 2006
We study finitely generated groups whose word problems are accepted by counter automata. We show that a group has word problem accepted by a blind n-counter automaton in the sense of Greibach if and only if it is virtually free abelian of rank n; this result, which answers a question of Gilman, is in a very precise sense an abelian analogue of the ...
arxiv   +1 more source

The rank of group of cyclotomic units in abelian fields

open access: yesJournal of Number Theory, 1982
AbstractA formula about the rank of group of cyclotomic units in abelian fields is established. From that formula, a series of equivalent conditions for independence of the system of cyclotomic units in abelian fields is stated and proved. For the particular case of cyclotomic fields, further properties of the rank are researched.
openaire   +2 more sources

An Algebraic Roadmap of Particle Theories

open access: yesAnnalen der Physik, Volume 537, Issue 4, April 2025.
The SO(10) grand unified theory, the Georgi–Glashow SU(5) grand unified theory, the Pati–Salam model, the Left–Right Symmetric model, and the Standard model have been studied extensively since the 1970s. Recasting these models in a division algebraic language elucidates how they are each in fact connected.
Nichol Furey
wiley   +1 more source

The ultrasimplicial property for simple dimension groups with unique state, the image of which has rank one [PDF]

open access: yesarXiv, 2014
Let $G$ be an ordered group that is a direct sum of a rank-one torsion-free abelian group and a finite-rank torsion-free abelian group, with order structure arising from the natural order on the first summand. A necessary condition and a sufficient condition are given for $G$ to have an ordered-group inductive limit representation using injective maps.
arxiv  

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