Results 81 to 90 of about 18,436 (217)

The Two Extremal Rays of Some Hyper–Kähler Fourfolds

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We consider projective Hyper–Kähler manifolds of dimension 4 that are deformation equivalent to Hilbert squares of K3 surfaces. In case such a manifold admits a divisorial contraction, the exceptional divisor is a conic bundle over a K3 surface. A classification of lattice embeddings implies that there are five types of such conic bundles.
Federica Galluzzi, Bert van Geemen
wiley   +1 more source

Inducing Coverings on Hilbert Schemes

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We find an explicit geometric description of all coverings of Hilb2(Σ)$\operatorname{Hilb}^{2}(\Sigma)$ when Σ$\Sigma$ is a normal, complex, quasi‐projective surface with finite fundamental group. We then apply this construction to show that if Σ$\Sigma$ is an irreducible symplectic surface then Hilb2(Σ)$\operatorname{Hilb}^{2}(\Sigma)$ is an ...
Lucas Li Bassi, Filippo Papallo
wiley   +1 more source

A Linear Generalization of the Nearly Gorenstein Property, With Applications to Veronese Subalgebras

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We study the nearly Gorenstein property for Veronese subalgebras of (semi‐)standard graded algebras. We introduce a condition (♮)$(\natural)$ for Cohen–Macaulay semi‐standard graded rings, motivated by the study of Ehrhart rings. We show that if a semi‐standard graded algebra R$ R$ satisfies (♮)$(\natural)$, then its Veronese subalgebras R(k)$
Sora Miyashita
wiley   +1 more source

Kernel Bounds for Parabolic Operators Having First‐Order Degeneracy at the Boundary

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We study kernel estimates for parabolic problems governed by singular elliptic operators ∑i,j=1N+1qijDij+cDyy,cγ+1>0,γ=qN+1,N+1,$$\begin{equation*} \sum _{i,j=1}^{N+1}q_{ij}D_{ij}+c\frac{D_y}{y},\qquad \frac{c}{\gamma }+1>0, \quad \gamma =q_{N+1,N+1}, \end{equation*}$$in the half‐space R+N+1={(x,y):x∈RN,y>0}$\mathbb {R}^{N+1}_+=\lbrace (x,y ...
L. Negro, C. Spina
wiley   +1 more source

A highly accurate numerical method for solving boundary value problem of generalized Bagley‐Torvik equation

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
A highly accurate numerical method is given for the solution of boundary value problem of generalized Bagley‐Torvik (BgT) equation with Caputo derivative of order 0<β<2$$ 0<\beta <2 $$ by using the collocation‐shooting method (C‐SM). The collocation solution is constructed in the space Sm+1(1)$$ {S}_{m+1}^{(1)} $$ as piecewise polynomials of degree at ...
Suzan Cival Buranay   +2 more
wiley   +1 more source

Exponential Stability of Higher Order Fractional Neutral Stochastic Differential Equation Via Integral Contractors

open access: yesMathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6425-6446, April 2025.
ABSTRACT The well‐posedness results for mild solutions to the fractional neutral stochastic differential system with Rosenblatt process with Hurst index Ĥ∈12,1$$ \hat{H}\in \left(\frac{1}{2},1\right) $$ is discussed in this article. To demonstrate the results, the concept of bounded integral contractors is combined with the stochastic result and ...
Dimplekumar N. Chalishajar   +3 more
wiley   +1 more source

Group‐Patch Joint Compression: Compressing Dynamic B0 and Static RF Spatial Modulations Across k‐Space Subregion Groups for Highly Accelerated MRI

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To accelerate MRI further, rapid B0 field modulations can be applied during oversampled readout to capture additional physical information, as in Wave‐CAIPI/FRONSAC/local B0 coils modulation techniques. These methods, however, turn the Fourier readout into a non‐Fourier‐encoded dimension that cannot be reconstructed by FFT, posing ...
Rui Tian, Klaus Scheffler
wiley   +1 more source

Generative MR Multitasking With Complex‐Harmonic Cardiac Encoding: Bridging the Gap Between Gated Imaging and Real‐Time Imaging

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To develop a unified image reconstruction framework that bridges real‐time and gated cardiac MRI, including quantitative MRI. Methods We introduce generative multitasking, which learns subject‐ and dataset‐specific implicit neural temporal bases from sequence timings and an interpretable latent space for cardiac and respiratory motion.
Xinguo Fang, Anthony G. Christodoulou
wiley   +1 more source

Fault Detection of Electric Motors via Symmetrized Dot Pattern‐Based Features

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT This study proposes a novel symmetrized dot pattern (SDP) approach using designed SDP‐based features, extracted from transformed vibration signals, for fault detection. These features describe the compactness, inclination, and shape of the “snowflake” diagram distributions.
Mario Spirto   +6 more
wiley   +1 more source

Measures of Distance in Quantum Mechanics

open access: yesUniverse
Combining gravity with quantum theory is still a work in progress. On the one hand, classical gravity is the geometry of space-time determined by the energy–momentum tensor of matter and the resulting nonlinear equations; on the other hand, the ...
Pawel Gusin   +2 more
doaj   +1 more source

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