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作者：Abe, Ken; Giga, Yoshikazu
作者单位：University of Tokyo
摘要：The analyticity of the Stokes semigroup with the Dirichlet boundary condition is established in spaces of bounded functions when the domain occupied with fluid is bounded or more generally admissible which admits a special estimate for the Helmholtz decomposition. The proof is based on a blow-up argument. This is the first proof of the analyticity in spaces of bounded functions which was left open more than thirty years.
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作者：Chermak, Andrew
作者单位：Kansas State University
摘要：We introduce objective partial groups, of which the linking systems and p-local finite groups of Broto, Levi, and Oliver, the transporter systems of Oliver and Ventura, and the -localities of Puig are examples, as are groups in the ordinary sense. As an application we show that if is a saturated fusion system over a finite p-group then there exists a centric linking system having as its fusion system, and that is unique up to isomorphism. The proof relies on the classification of the finite si...
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作者：Cantat, Serge; Lamy, Stephane; de Cornulier, Yves
作者单位：Universite de Rennes; University of Warwick; Centre National de la Recherche Scientifique (CNRS); Universite Paris Saclay
摘要：Let k be an algebraically closed field. We show that the Cremona group of all birational transformations of the projective plane is not a simple group. The strategy makes use of hyperbolic geometry, geometric group theory and algebraic geometry to produce elements in the Cremona group that generate non-trivial normal subgroups.
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作者：Murai, Satoshi; Nevo, Eran
作者单位：Yamaguchi University; Ben-Gurion University of the Negev
摘要：In 1971, McMullen and Walkup posed the following conjecture, which is called the generalized lower bound conjecture: If P is a simplicial d-polytope then its h-vector (h (0), h (1), aEuro broken vertical bar, h (d) ) satisfies . Moreover, if h (r-1) = h (r) for some then P can be triangulated without introducing simplices of dimension a parts per thousand currency signd - r. The first part of the conjecture was solved by Stanley in 1980 using the hard Lefschetz theorem for projective toric var...
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作者：Oliver, Bob
作者单位：Universite Paris 13; Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute for Mathematical Sciences (INSMI)
摘要：We present a version of a proof by Andy Chermak of the existence and uniqueness of centric linking systems associated with arbitrary saturated fusion systems. This proof differs from the one in [Ch2] in that it is based on the computation of derived functors of certain inverse limits. This leads to a much shorter proof, but one which is aimed mostly at researchers familiar with homological algebra.
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作者：Aspero, David; Larson, Paul; Moore, Justin Tatch
作者单位：University of East Anglia; University System of Ohio; Miami University; Cornell University
摘要：Woodin has demonstrated that, in the presence of large cardinals, there is a single model of ZFC which is maximal for I (2)-sentences over the structure (H(omega (2)), a, NS (omega 1)), in the sense that its (H(omega (2)), a, NS (omega 1)) satisfies every I (2)-sentence sigma for which (H(omega (2)), a, NS (omega 1)) aS sigma can be forced by set-forcing. In this paper we answer a question of Woodin by showing that there are two I (2)-sentences over the structure (H(omega (2)), a, omega (1)) w...
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作者：Meyer, Daniel
作者单位：Constructor University
摘要：We consider Thurston maps, i.e., branched covering maps f:S (2) -> S (2) that are post-critically finite. In addition, we assume that f is expanding in a suitable sense. It is shown that each sufficiently high iterate F = f (n) of f is semi-conjugate to z (d) :S (1) -> S (1), where d = deg F. More precisely, for such an F we construct a Peano curve gamma:S (1) -> S (2) (onto), such that Fa similar to gamma(z) = gamma(z (d) ) (for all zaS (1)).
