Results 71 to 80 of about 4,217,963 (196)

Testing Hypotheses of Covariate Effects on Topics of Discourse

open access: yesStatistical Analysis and Data Mining: An ASA Data Science Journal, Volume 19, Issue 2, April 2026.
ABSTRACT We introduce an approach to topic modeling with document‐level covariates that remains tractable in the face of large text corpora. This is achieved by de‐emphasizing the role of parameter estimation in an underlying probabilistic model, assuming instead that the data come from a fixed but unknown distribution whose statistical functionals are
Gabriel Phelan, David A. Campbell
wiley   +1 more source

A New Orthogonal Geomagnetic Coordinate System: The Generalized Eccentric Dipole

open access: yesJournal of Geophysical Research: Space Physics, Volume 131, Issue 4, April 2026.
Abstract The study of near‐Earth plasma environment relies heavily on accurate geomagnetic coordinate systems, mainly because the plasma motion is controlled by the E×B $\boldsymbol{E}\times \boldsymbol{B}$ drift and thus is constrained by the structure of the magnetic field.
Antoine Resseguier   +2 more
wiley   +1 more source

Auroral Signatures of Ballooning Instability and Plasmoid Formation Processes in the Near‐Earth Magnetotail

open access: yesJournal of Geophysical Research: Space Physics, Volume 131, Issue 4, April 2026.
Abstract The nonlinear development of ballooning instability and the subsequently induced plasmoid formation in the near‐Earth magnetotail demonstrated in MHD simulations has been proposed as a potential trigger mechanism for substorm onset over the past decade, and their connections to the in situ satellite and ground all‐sky auroral optical ...
Ping Zhu   +4 more
wiley   +1 more source

On virtual chirality of 3‐manifolds

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 4, April 2026.
Abstract We prove that if a prime 3‐manifold M$M$ is not finitely covered by the 3‐sphere or a product manifold, then M$M$ is virtually chiral, that is, it has a finite cover that does not admit an orientation‐reversing self‐homeomorphism. In general, if a 3‐manifold contains a virtually chiral prime summand, then it is virtually chiral.
Hongbin Sun, Zhongzi Wang
wiley   +1 more source

On sensitivity to initial conditions and uniqueness of conjugacies for structurally stable diffeomorphisms [PDF]

open access: yesNonlinearity, 2017
17 pages, 5 figures, final version to appear on ...
Rocha, Jorge, Varandas, Paulo
openaire   +2 more sources

Uniform growth in small cancellation groups

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 4, April 2026.
Abstract An open question asks whether every group acting acylindrically on a hyperbolic space has uniform exponential growth. We prove that the class of groups of uniform uniform exponential growth acting acylindrically on a hyperbolic space is closed under taking certain geometric small cancellation quotients.
Xabier Legaspi, Markus Steenbock
wiley   +1 more source

Expansion of normal subsets of odd‐order elements in finite groups

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 4, April 2026.
Abstract Let G$G$ be a finite group and K$K$ a normal subset consisting of odd‐order elements. The rational closure of K$K$, denoted DK$\mathbf {D}_K$, is the set of elements x∈G$x \in G$ with the property that ⟨x⟩=⟨y⟩$\langle x \rangle = \langle y \rangle$ for some y$y$ in K$K$.
Chris Parker, Jack Saunders
wiley   +1 more source

Some examples of rigid representations [PDF]

open access: yes, 2000
Consider the Deligne-Simpson problem: {\em give necessary and sufficient conditions for the choice of the conjugacy classes $C_j\subset GL(n,{\bf C})$ (resp.
Kostov, Vladimir
core   +1 more source

Ordinary primes for GL2$\operatorname{GL}_2$‐type abelian varieties and weight 2 modular forms

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract Let A$A$ be a g$g$‐dimensional abelian variety defined over a number field F$F$. It is conjectured that the set of ordinary primes of A$A$ over F$F$ has positive density, and this is known to be true when g=1,2$g=1, 2$, or for certain abelian varieties with extra endomorphisms.
Tian Wang, Pengcheng Zhang
wiley   +1 more source

Circle packings, renormalizations, and subdivision rules

open access: yesProceedings of the London Mathematical Society, Volume 132, Issue 4, April 2026.
Abstract In this paper, we use iterations of skinning maps on Teichmüller spaces to study circle packings and develop a renormalization theory for circle packings whose nerves satisfy certain subdivision rules. We characterize when the skinning map has bounded image.
Yusheng Luo, Yongquan Zhang
wiley   +1 more source

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