Xem 1-14 trên 14 kết quả Counterexample
  • We construct a proper C 2 -smooth function on R4 such that its Hamiltonian flow has no periodic orbits on at least one regular level set. This result can be viewed as a C 2 -smooth counterexample to the Hamiltonian Seifert conjecture in dimension four. 1. Introduction The “Hamiltonian Seifert conjecture” is the question whether or not there exists a proper function on R2n whose Hamiltonian flow has no periodic orbits on at least one regular level set.

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  • A long-standing conjecture due to Michael Freedman asserts that the 4-dimensional topological surgery conjecture fails for non-abelian free groups, or equivalently that a family of canonical examples of links (the generalized Borromean rings) are not A − B slice. A stronger version of the conjecture, that the Borromean rings are not even weakly A − B slice, where one drops the equivariant aspect of the problem, has been the main focus in the search for an obstruction to surgery.

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  • Tuyển tập các báo cáo nghiên cứu khoa học về toán học trên tạp chí toán học quốc tế đề tài: A counterexample to a conjecture of Erd˝s, Graham and Spencer o...

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  • Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí Department of Mathematic dành cho các bạn yêu thích môn toán học đề tài: More Counterexamples to the Alon-Saks-Seymour and Rank-Coloring Conjectures...

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  • Ch÷ìng 1 Introduction - Giới thiệu 1. We prove that in some families of com- pact there are no universal elements. 1. Ta chứng minh rằng trong một số họ compact không tồn tại các phần tử toàn thể. 2. It is also shown that... 2. Nó cung chỉ ra rằng 3. Some relevant counterexamples are in- dicated. 3. Một số thí dụ có liên quan ÷ợc chỉ ra. 4. We wish to investigate ... 4. Ta muốn khảo sát .... 5. Our purpose is to ... 5. Mục ích của chúng ta là ... 6. It is of interest to know whether... 6.

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  • In this paper we study Lipschitz solutions of partial differential relations of the form (1) ∇u(x) ∈ K a.e. in Ω, where u is a (Lipschitz) mapping of an open set Ω ⊂ Rn into Rm , ∇u(x) is its gradient (i.e. the matrix ∂ui (x)/∂xj , 1 ≤ i ≤ m, 1 ≤ j ≤ n, defined for almost every x ∈ Ω), and K is a subset of the set M m×n of all real m × n matrices. In addition to relation (1), boundary conditions and other conditions on u will also be considered. Relation (1)...

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  • We investigate the relationship between an open simply-connected region Ω ⊂ S2 and the boundary Y of the hyperbolic convex hull in H3 of S2 \ Ω. A counterexample is given to Thurston’s conjecture that these spaces are related by a 2-quasiconformal homeomorphism which extends to the identity map on their common boundary, in the case when the homeomorphism is required to respect any group of M¨bius transformations which preserves Ω.

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  • In 1961, Baker, Gammel and Wills conjectured that for functions f meromorphic in the unit ball, a subsequence of its diagonal Pad´ approximants e converges uniformly in compact subsets of the ball omitting poles of f . There is also apparently a cruder version of the conjecture due to Pad´ himself, going e back to the early twentieth century. We show here that for carefully chosen q on the unit circle, the Rogers-Ramanujan continued fraction 1+ qz| q 2 z| q 3 z| + + + ··· |1 |1 |1 provides a counterexample to the conjecture. We also highlight some...

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  • We give infinite series of groups Γ and of compact complex surfaces of general type S with fundamental group Γ such that 1) Any surface S with the same Euler number as S, and fundamental group Γ, is diffeomorphic to S. 2) The moduli space of S consists of exactly two connected components, exchanged by complex conjugation. Whence, i) On the one hand we give simple counterexamples to the DEF = DIFF question whether deformation type and diffeomorphism type coincide for algebraic surfaces. ii) On the other hand we get examples of moduli spaces without real points. iii)...

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  • We exhibit a counterexample to Elliott’s classification conjecture for simple, separable, and nuclear C∗ -algebras whose construction is elementary, and demonstrate the necessity of extremely fine invariants in distinguishing both approximate unitary equivalence classes of automorphisms of such algebras and isomorphism classes of the algebras themselves.

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  • Trong chương này là một số ví dụ của các ứng dụng mới của mô hình thích hợp, lựa chọn chủ yếu để minh họa counterexamples quan trọng. Có thẩm quyền nghiên cứu mô hình thích hợp mô hình phản ứng của các loài như một 'U đảo ngược, và không tuyến tính phản ứng. Những ví dụ minh họa một số phản ứng khác thường hơn và sử dụng các chức năng ứng phó.

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  • Hindawi Publishing Corporation Fixed Point Theory and Applications Volume 2011, Article ID 484717, 3 pages doi:10.1155/2011/484717 Letter to the Editor A Counterexample to “An Extension of Gregus Fixed Point Theorem” Sirous Moradi Department of Mathematics, Faculty of Science, Arak University, Arak 38156-8-8349, Iran Correspondence should be addressed to Sirous Moradi, Received 29 November 2010; Accepted 21 February 2011 Copyright q 2011 Sirous Moradi.

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  • Throughout the world, members of the education research community have long decried the lack of attention to research and scholarship that is evident in most education policies promulgated by state, provincial, and national legislatures. The Elementary and Secondary Education Act of 2001 (ESEA 2001), which was recently signed into law in the United States, is an interesting case to consider in this regard.

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  • We argue that the machine translation community is overly reliant on the Bleu machine translation evaluation metric. We show that an improved Bleu score is neither necessary nor sufficient for achieving an actual improvement in translation quality, and give two significant counterexamples to Bleu’s correlation with human judgments of quality. This offers new potential for research which was previously deemed unpromising by an inability to improve upon Bleu scores.

    pdf8p bunthai_1 06-05-2013 25 1   Download


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