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This paper presents an approach to generalize the concept of isogeometric analysis (IGA) by allowing different spaces for parameterization of the computational domain and for approximation of the solution field. The method inherits the main…

Numerical Analysis · Mathematics 2017-07-11 Elena Atroshchenko , Gang Xu , Satyendra Tomar , Stephane P. A. Bordas

We study the stability of a recently proposed model of scalar-field matter called mimetic dark matter or imperfect dark matter. It has been known that mimetic matter with higher derivative terms suffers from gradient instabilities in scalar…

General Relativity and Quantum Cosmology · Physics 2017-07-19 Shin'ichi Hirano , Sakine Nishi , Tsutomu Kobayashi

In this paper, we introduce the new optimal perturbation iteration method based on the perturbation iteration algorithms for the approximate solutions of nonlinear differential equations of many types. The proposed method is illustrated by…

Numerical Analysis · Mathematics 2016-09-21 Sinan Deniz , Necdet Bildik

We develop a general formalism for analyzing linear perturbations in multiple-field cosmological inflation based on the gauge-ready approach. Our inflationary model consists of an arbitrary number of scalar fields with non-minimal kinetic…

Astrophysics · Physics 2009-11-13 Joydev Lahiri , Gautam Bhattacharya

Bayesian spatial modeling provides a flexible framework for whole-brain fMRI analysis by explicitly incorporating spatial dependencies, overcoming the limitations of traditional massive univariate approaches that lead to information waste.…

Methodology · Statistics 2025-11-18 Yuan Zhong , Gang Chen , Paul A. Taylor , Jian Kang

The ARIMA (Autoregressive Integrated Moving Average model) has extensive applications in the field of time series forecasting. However, the predictive performance of the ARIMA model is limited when dealing with data gaps or significant…

Statistical Finance · Quantitative Finance 2023-11-21 Xitai Yu

We propose a perturbative improvement of the hierarchical approximation for gaussian models. The procedure is based on a relabeling of the momenta which allows one to express the symmetries of the hierarchical model using a simple…

High Energy Physics - Theory · Physics 2007-05-23 Yannick Meurice

We discuss possible instabilities in higher-derivative matter fields theories. These theories has two free parameters $\beta_1$ and $\beta_4$. By using dynamical system approach we explicitly demonstrate that for stability of Minkowski…

General Relativity and Quantum Cosmology · Physics 2016-10-12 Petr V. Tretyakov

We operate through the lens of ordinary differential equations and control theory to study the concept of observability in the context of neural state-space models and the Mamba architecture. We develop strategies to enforce observability,…

Machine Learning · Computer Science 2025-05-06 Andrew Gracyk

The phase-integral approximation devised by Fr\"oman and Fr\"oman, is used for computing cosmological perturbations in the power-law inflationary model. The phase-integral formulas for the scalar and tensor power spectra are explicitly…

Astrophysics · Physics 2008-11-26 Clara Rojas , Victor M. Villalba

The Hubble tension seems to be a crisis with $\sim5\sigma$ discrepancy between the most recent local distance ladder measurement from type Ia supernovae calibrated by Cepheids and the global fitting constraint from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-19 Rong-Gen Cai , Zong-Kuan Guo , Shao-Jiang Wang , Wang-Wei Yu , Yong Zhou

In this work, in the context of Linear and Quadratic Programming, we interpret Primal Dual Regularized Interior Point Methods (PDR-IPMs) in the framework of the Proximal Point Method. The resulting Proximal Stabilized IPM (PS-IPM) is…

Optimization and Control · Mathematics 2022-05-05 Stefano Cipolla , Jacek Gondzio

Recent advances in machine learning, specifically transformer architecture, have led to significant advancements in commercial domains. These powerful models have demonstrated superior capability to learn complex relationships and often…

Machine Learning · Computer Science 2024-05-29 Matthew L. Olson , Shusen Liu , Jayaraman J. Thiagarajan , Bogdan Kustowski , Weng-Keen Wong , Rushil Anirudh

Balancing fine-grained local modeling with long-range dependency capture under computational constraints remains a central challenge in sequence modeling. While Transformers provide strong token mixing, they suffer from quadratic…

Machine Learning · Computer Science 2026-03-20 Youjin Wang , Jiaqiao Zhao , Rong Fu , Run Zhou , Ruizhe Zhang , Jiani Liang , Suisuai Cao , Feng Zhou

We give a brief review of two nonperturbative phenomena typical of noncommutative field theory which are known to lead to the perturbative instability known as the UV-IR mixing. The first phenomena concerns the emergence/evaporation of…

High Energy Physics - Theory · Physics 2010-11-23 Badis Ydri

Within the framework of inflationary models that incorporate a spontaneous reduction of the wave function for the emergence of the seeds of cosmic structure, we study the effects on the primordial scalar power spectrum by choosing a novel…

General Relativity and Quantum Cosmology · Physics 2017-10-16 Gabriel R. Bengochea , Gabriel León

Recently a one-parameter extension of the covariant Heisenberg algebra with the extension parameter $l$ ($l$ is a non-negative constant parameter which has a dimension of $[momentum]^{-1}$) in a $(D+1)$-dimensional Minkowski space-time has…

High Energy Physics - Theory · Physics 2020-04-15 M. Ranaiy , S. K. Moayedi

The method of maximum entropy is used to model curved physical space in terms of points defined with a finite resolution. Such a blurred space is automatically endowed with a metric given by information geometry. The corresponding…

General Relativity and Quantum Cosmology · Physics 2019-09-24 Ariel Caticha

In this review we argue that four-dimensional effective field theory descriptions with de Sitter isometries are allowed in the presence of time-dependent internal degrees of freedom in type IIB string landscape. Both moduli stabilizations…

High Energy Physics - Theory · Physics 2019-12-06 Keshav Dasgupta , Maxim Emelin , Mir Mehedi Faruk , Radu Tatar

For exponents in the subcritical range, we revisit some optimal interpolation inequalities on the sphere with carr\'e du champ methods and use the remainder terms to produce improved inequalities. The method provides us with lower estimates…

Analysis of PDEs · Mathematics 2019-08-23 Jean Dolbeault , Maria J. Esteban