共查询到20条相似文献,搜索用时 266 毫秒
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In this paper, by using Picard–Fuchs equations and Chebyshev criterion, we study the upper bounds of the number of limit cycles given by the first order Melnikov function for discontinuous differential systems, which can bifurcate from the periodic orbits of quadratic reversible centers of genus one (r19): , , and (r20): , , and the periodic orbits of the quadratic isochronous centers , , and , . The systems (r19) and (r20) are perturbed inside the class of polynomial differential systems of degree n and the system and are perturbed inside the class of quadratic polynomial differential systems. The discontinuity is the line . It is proved that the upper bounds of the number of limit cycles for systems (r19) and (r20) are respectively and counting the multiplicity, and the maximum numbers of limit cycles bifurcating from the period annuluses of the isochronous centers and are exactly 5 and 6 (counting the multiplicity) on each period annulus respectively. 相似文献
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Tristan Roy 《Journal of Differential Equations》2018,264(9):6013-6024
The purpose of this corrigendum is to point out some errors that appear in [1]. Our main result remains valid, i.e scattering of solutions of the loglog energy-supercritical Schrödinger equation , , , with , radial data but with slightly different values of , i.e if and if . We propose some corrections. 相似文献
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Carme Cascante Joan Fàbrega Joaquín M. Ortega 《Journal of Mathematical Analysis and Applications》2018,457(1):722-750
In this paper we characterize the boundedness of the bilinear form defined by in the product of homogeneous Sobolev spaces , . We deduce a characterization of the space of pointwise multipliers from to its dual in terms of trace measures. 相似文献
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For fractional Navier–Stokes equations and critical initial spaces X, one used to establish the well-posedness in the solution space which is contained in . In this paper, for heat flow, we apply parameter Meyer wavelets to introduce Y spaces where is not contained in . Consequently, for , we establish the global well-posedness of fractional Navier–Stokes equations with small initial data in all the critical oscillation spaces. The critical oscillation spaces may be any Besov–Morrey spaces or any Triebel–Lizorkin–Morrey spaces where . These critical spaces include many known spaces. For example, Besov spaces, Sobolev spaces, Bloch spaces, Q-spaces, Morrey spaces and Triebel–Lizorkin spaces etc. 相似文献
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Douglas P. Hardin Michael C. Northington Alexander M. Powell 《Applied and Computational Harmonic Analysis》2018,44(2):294-311
A sharp version of the Balian–Low theorem is proven for the generators of finitely generated shift-invariant spaces. If generators are translated along a lattice to form a frame or Riesz basis for a shift-invariant space V, and if V has extra invariance by a suitable finer lattice, then one of the generators must satisfy , namely, . Similar results are proven for frames of translates that are not Riesz bases without the assumption of extra lattice invariance. The best previously existing results in the literature give a notably weaker conclusion using the Sobolev space ; our results provide an absolutely sharp improvement with . Our results are sharp in the sense that cannot be replaced by for any . 相似文献
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A.L. Agore 《Journal of Pure and Applied Algebra》2018,222(4):914-930
We classify all Hopf algebras which factor through two Taft algebras and respectively . To start with, all possible matched pairs between the two Taft algebras are described: if then the matched pairs are in bijection with the group of d-th roots of unity in k, where while if then besides the matched pairs above we obtain an additional family of matched pairs indexed by . The corresponding bicrossed products (double cross product in Majid's terminology) are explicitly described by generators and relations and classified. As a consequence of our approach, we are able to compute the number of isomorphism types of these bicrossed products as well as to describe their automorphism groups. 相似文献
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Let q be a positive integer. Recently, Niu and Liu proved that, if , then the product is not a powerful number. In this note, we prove (1) that, for any odd prime power ? and , the product is not a powerful number, and (2) that, for any positive odd integer ?, there exists an integer such that, for any positive integer , the product is not a powerful number. 相似文献
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Given a prime number p, a field F with and a positive integer n, we study the class-preserving modifications of Kato–Milne classes of decomposable differential forms. These modifications demonstrate a natural connection between differential forms and p-regular forms. A p-regular form is defined to be a homogeneous polynomial form of degree p for which there is no nonzero point where all the order partial derivatives vanish simultaneously. We define a field to be a field over which every p-regular form of dimension greater than is isotropic. The main results are that for a field F, the symbol length of is bounded from above by and for any , . 相似文献
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Let be an isometric immersion from a Riemannian n-manifold into a Euclidean m-space. Denote by Δ and the Laplace operator and the position vector of M, respectively. Then M is called biharmonic if . The following Chen?s Biharmonic Conjecture made in 1991 is well-known and stays open: The only biharmonic submanifolds of Euclidean spaces are the minimal ones. In this paper we prove that the biharmonic conjecture is true for -ideal and -ideal hypersurfaces of a Euclidean space of arbitrary dimension. 相似文献
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Wassim Nasserddine 《Comptes Rendus Mathematique》2017,355(5):543-548
Let G be a separable locally compact group with type-I left regular representation, its dual and its Fourier algebra. We prove an analogue of Parseval's theorem and that the mapping is an isometric isomorphism of Banach spaces from onto . 相似文献