首页期刊导航|Journal of geometry and physics
期刊信息/Journal information
Journal of geometry and physics
Pitagora Editrice
Journal of geometry and physics

Pitagora Editrice

0393-0440

Journal of geometry and physics/Journal Journal of geometry and physicsSCIISTP
正式出版
收录年代

    Observer-invariant time derivatives on moving surfaces

    Nitschke, IngoVoigt, Axel
    24页
    查看更多>>摘要:Observer-invariance is regarded as a minimum requirement for an appropriate definition of time derivatives. We derive various time derivatives systematically from a spacetime setting, where observer-invariance is a special case of a covariance principle and covered by Ricci-calculus. The analysis is considered for tangential n-tensor fields on moving surfaces and provides formulations which are applicable for numerical computations. For various special cases, e.g., vector fields (n = 1) and symmetric and trace-less tensor fields (n = 2) we compare material and convected derivatives and demonstrate the different underlying physics. (C) 2021 Elsevier B.V. All rights reserved.

    On Einstein hypersurfaces of I x( f )Q(n)(c)

    Borges, VDa Silva, A.
    12页
    查看更多>>摘要:In this paper, we investigate Einstein hypersurfaces of the warped product I x (f) Q(n)(c), where Q(n)(c) is a space form of curvature c. We prove that M has at most three distinct principal curvatures and that it is locally a multiply warped product with at most two fibers. We also show that exactly one or two principal curvatures on an open set imply constant sectional curvature on that set. For exactly three distinct principal curvatures this is no longer true, and we classify such hypersurfaces provided it does not have constant sectional curvature and a certain principal curvature vanishes identically. (C) 2021 Elsevier B.V. All rights reserved.

    Evolution of the Steklov eigenvalue along the conformal mean curvature flow

    Pak Tung HoShin, Jinwoo
    15页
    查看更多>>摘要:In this paper, we study the evolution of the Steklov eigenvalue along the conformal mean curvature flow on n-dimensional compact manifolds with boundary for n >= 3. (C) 2021 The Author(s). Published by Elsevier B.V.

    Nice pseudo-Riemannian nilsolitons

    Conti, DiegoRossi, Federico A.
    20页
    查看更多>>摘要:We study nice nilpotent Lie algebras admitting a diagonal nilsoliton metric. We classify nice Riemannian nilsolitons up to dimension 9. For general signature, we show that determining whether a nilpotent nice Lie algebra admits a nilsoliton metric reduces to a linear problem together with a system of as many polynomial equations as the corank of the root matrix. We classify nice nilsolitons of any signature: in dimension <= 7; in dimension 8 for corank <= 1; in dimension 9 for corank zero. (C) 2021 Elsevier B.V. All rights reserved.

    Quotient of the Euler system on one class of curves

    Duyunova, AnnaLychagin, ValentinTychkov, Sergey
    9页
    查看更多>>摘要:We consider the Euler system describing a one-dimensional inviscid flows in space along curves of a certain class. Using differential invariants for the Euler system, we obtain its quotient equation. The solutions of the quotient equation that are constant along characteristic vector field provide some solutions of the Euler system. We discuss solving the quotient using asymptotic expansions of unknown functions and virial expansion of thermodynamic state equations. Thus the quotient is reduced to a series of ODE systems. (C) 2021 Elsevier B.V. All rights reserved.

    Critical metrics on 4-manifolds with harmonic anti-self dual Weyl tensor

    Viana, Emanuel
    8页
    查看更多>>摘要:In this paper, we study 4-dimensional simply connected, compact critical metric of the volume functional with harmonic anti-self dual Weyl tensor. We show that a 4-dimensional simply connected, compact critical metric of the volume functional with harmonic anti-self dual Weyl tensor and satisfying a suitable pinching condition is isometric to a geodesic ball in a simply connected space form R-4, H-4 or S-4. (C) 2021 Elsevier B.V. All rights reserved.

    Cohomologies of PoiMod pairs and compatible structures on Poisson algebras

    Liu, JiefengSheng, Yunhe
    22页
    查看更多>>摘要:In this paper, first we give the cohomology theory of a Poisson algebra with a module (called a PoiMod pair) and study the linear deformation theory of a PoiMod pair. We introduce the notion of a Nijenhuis structure on a PoiMod pair, which gives a trivial linear deformation. Then by adding compatibility conditions between Nijenhuis structures and O-operators, we introduce the notion of an ON-structure on a PoiMod pair and show that an ON-structure gives rise to a hierarchy of pairwise compatible O-operators. Finally we introduce the notions of PN- and Omega N-structures on Poisson algebras and study their relations. (C) 2022 Elsevier B.V. All rights reserved.

    Calculus of multilinear differential operators, operator L-infinity-algebras and IBL infinity-algebras

    Bashkirov, DenisMarkl, Martin
    40页
    查看更多>>摘要:We propose an operadic framework suitable for describing algebraic structures with operations being multilinear differential operators of varying orders or, more generally, formal series of such operators. The framework is built upon the notion of a multifiltration of a linear operad generalizing the concept of a filtration of an associative algebra. We describe a particular way of constructing and analyzing multifiltrations based on a presentation of a linear operad in terms of generators and relations. In particular, that allows us to observe a special role played in this context by Lie, Lie-admissible and Lie(infinity)-structures. As a main application, and the original motivation for the present work, we show how a certain generalization of the well-known big bracket construction of Lecomte-Roger and Kosmann-Schwarzbach encompassing the case of homotopy involutive Lie bialgebras can be obtained. (C) 2021 Elsevier B.V. All rights reserved.

    A noncommutative spacetime realization of quantum black holes, Regge trajectories and holography

    Perelman, Carlos Castro
    9页
    查看更多>>摘要:It is shown that the radial spectrum associated with a fuzzy sphere in a noncommutative phase space characterized by the Yang algebra, leads exactly to a Regge-like spectrum GM(l)(2) = l = 1, 2,3, ..., for all positive values of l, and which is consistent with the extremal quantum Kerr black hole solution that occurs when the outer and inner horizon radius coincide r(+) = r_ = GM. The condition GM(l)(2) = 1 is tantamount to the mass-angular momentum relation M-l(2) =lM(p)(2), implying a mass-squared quantization in multiples of the Planck-mass-squared. Another important feature (also pointed out by Tanaka) is the holographic nature of these results that are based in recasting the Yang algebra associated with an 8D noncommuting phase space, involving, x(mu), p(nu), mu, nu = 0, 1, 2, 3, in terms of the undeformed realizations of the Lorentz algebra generators J(AB) corresponding to a 6D-spacetime, and associated to a 12D-phase-space with coordinates X-A, P-A; A = 0, 1, 2, ..., 5. We finalize with a discussion of the noncommuting 3D isotropic and Born oscillators. Finding solutions to these oscillators merit investigation because they introduce explicit dynamics to the quantum black holes. We hope that the findings in this work, relating the Regge-like spectrum l = GM(2) and the quantized area of black hole horizons in Planck bits, via the Yang algebra in Noncommutative phase spaces, will help us elucidate some of the impending issues pertaining the black hole information paradox and the role that string theory and quantum information will play in its resolution. (C) 2021 Elsevier B.V. All rights reserved.

    On the isomorphism of non-abelian extensions of n-Lie algebras

    Afi, MahaBasdouri, Okba
    9页
    查看更多>>摘要:In this paper, we are interested to study non-abelian extensions of n-Lie algebra. More precisely, we focus to construct the isomorphism theorem of non-abelian extensions. At last, we demonstrate that isomorphism classes of non-abelian extensions of n-Lie algebra are described using equivalence classes of Maurer-Cartan elements in a DGLA. (C) 2021 Elsevier B.V. All rights reserved.