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Working with perturbations about an FLRW spacetime, we compute the gauge-invariant curvature perturbation to second order solely in terms of scalar field fluctuations. Using the curvature perturbation on uniform density hypersurfaces as our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Adam J. Christopherson , Ellie Nalson , Karim A. Malik

A generic method for combinatorial constructions of intrinsic geometrical spaces is presented. It is based on the well known inverse sequences of finite graphs that determine (in the limit) topological spaces. If a pattern of the…

Computational Geometry · Computer Science 2020-10-09 Stanislaw Ambroszkiewicz

The theory of classical types of curves in normed planes is not strongly developed. In particular, the knowledge on existing concepts of curvatures of planar curves is widespread and not systematized in the literature. Giving a…

Differential Geometry · Mathematics 2017-02-07 Vitor Balestro , Horst Martini , Emad Shonoda

We apply symmetry and invariance methods to analyse systems of difference equations. Non trivial symmetries are derived and their exact solutions obtained.

Dynamical Systems · Mathematics 2017-11-28 JJ Bashingwa , AH Kara , M Folly-Gbetoula

We discuss in some generality aspects of noncommutative differential geometry associated with reality conditions and with differential calculi. We then describe the differential calculus based on derivations as generalization of vector…

q-alg · Mathematics 2008-02-03 Michel Dubois-Violette

In this review paper, we consider three kinds of systems of differential equations, which are relevant in physics, control theory and other applications in engineering and applied mathematics; namely: Hamilton equations, singular…

Mathematical Physics · Physics 2016-04-11 Xavier Gràcia , Miguel C. Muñoz-Lecanda , Narciso Román-Roy

In this paper we develop methods to extend the minimal hypersurface approach to positive scalar curvature problems to all dimensions. This includes a proof of the positive mass theorem in all dimensions without a spin assumption. It also…

Differential Geometry · Mathematics 2017-04-20 Richard Schoen , Shing-Tung Yau

We point out how some recent developments in the theory of constant scalar curvature K\"ahler metrics can be used to clarify the existence issue for such metrics in the special case of geometrically ruled complex surfaces.

Differential Geometry · Mathematics 2007-05-23 Vestislav Apostolov , Christina W. Tønnesen-Friedman

We give a brief introduction to some of the recent works on finding geometric structures on triangulated surfaces using variational principles.

Geometric Topology · Mathematics 2008-04-01 Feng Luo

This tutorial explains Linear Discriminant Analysis (LDA) and Quadratic Discriminant Analysis (QDA) as two fundamental classification methods in statistical and probabilistic learning. We start with the optimization of decision boundary on…

Machine Learning · Statistics 2019-06-07 Benyamin Ghojogh , Mark Crowley

Hypercontractive inequalities are a useful tool in dealing with extremal questions in the geometry of high-dimensional discrete and continuous spaces. In this survey we trace a few connections between different manifestations of…

Discrete Mathematics · Computer Science 2011-01-18 Punyashloka Biswal

In recent years there has been a lot of interest in discussing frame dependences/independences of the cosmological perturbations under the conformal transformations. This problem has previously been investigated in terms of the covariant…

General Relativity and Quantum Cosmology · Physics 2018-03-14 Yunlong Zheng , Yicen Mou , Haomin Rao , Mingzhe Li

The article treats the geometrical theory of partial differential equations in the absolute sense, i.e., without any additional structures and especially without any preferred choice of independent and dependent variables. The equations are…

Differential Geometry · Mathematics 2014-01-14 Veronika Chrastinová , Václav Tryhuk

We investigate the interaction between systolic geometry and positive scalar curvature through spinorial methods. Our main theorem establishes an upper bound for the two-dimensional stable systole on certain high-dimensional manifolds with…

Differential Geometry · Mathematics 2025-09-30 Shunichiro Orikasa

We study conformal metrics with prescribed Gaussian curvature on surfaces with conical singularities and geodesic boundary in supercritical regimes. Exploiting a variational argument, we derive a general existence result for surfaces with…

Analysis of PDEs · Mathematics 2022-10-10 Luca Battaglia , Aleks Jevnikar , Zhi-An Wang , Wen Yang

A dilatation structure is a concept in between a group and a differential structure. In this article we study fundamental properties of dilatation structures on metric spaces. This is a part of a series of papers which show that such a…

Metric Geometry · Mathematics 2019-02-18 Marius Buliga

This note is devotes to some remarks regarding the use of variational methods, of minimax type, to establish continuity type results

Analysis of PDEs · Mathematics 2011-04-06 Louis Jeanjean

In the process of projecting the surface of a three-dimensional object onto a two-dimensional surface, due to the perspective distortion, the image on the surface of the object will have different degrees of distortion according to the…

Image and Video Processing · Electrical Eng. & Systems 2022-12-29 Yuhan Xu , Renqing Luo

This paper deals with retraction - intended as isomorphic embedding - in intersection types building left and right inverses as terms of a lambda calculus with a bottom constant. The main result is a necessary and sufficient condition two…

Logic in Computer Science · Computer Science 2017-02-09 Mario Coppo , Mariangiola Dezani-Ciancaglini , Alejandro Díaz-Caro , Ines Margaria , Maddalena Zacchi

After sketching recent advances and subtleties in classical relativistically covariant field theories, we give in this short Note some indications as to how the deformation quantization approach can be used to solve or at least give a…

Quantum Algebra · Mathematics 2007-05-23 Giuseppe Dito
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