72,497 research outputs found

    Finally, results from Gravity Probe-B

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    Nearly fifty years after its inception, the Gravity Probe B satellite mission delivers the first measurements of how a spinning gyroscope precesses in the gravitational warping of spacetime.Comment: A Viewpoint article, published in Physics 4, 43 (2011), available at http://physics.aps.org/articles/v4/43 Submitted to the arXiv by permission of the American Physical Societ

    Beantown Baptism in the free speech\u27 zone

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    Democratic practice depends on civil discourse. In the long run an intelligent word will always be more effective than a whole book of insults, or a whole bottle of water

    On finite derived quotients of 3-manifold groups

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    This paper studies the set of finite groups appearing as π1(M)/π1(M)(n)\pi_1(M)/\pi_1(M)^{(n)}, where MM is a closed, orientable 3-manifold and π1(M)(n)\pi_1(M)^{(n)} denotes the nn-th term of the derived series of π1(M)\pi_1(M). Our main result is that if MM is a closed, orientable 3-manifold, n2n\ge 2, and Gπ1(M)/π1(M)(n)G\cong \pi_1(M)/\pi_1(M)^{(n)} is finite, then the cup product pairing H2(G)H2(G)H4(G)H^2(G)\otimes H^2(G)\to H^4(G) has cyclic image CC, and the pairing H2(G)H2(G)CH^2(G)\otimes H^2(G)\stackrel{\smile}{\longrightarrow} C is isomorphic to the linking pairing H1(M)TorsH1(M)TorsQ/ZH_1(M)_{\textrm{Tors}}\otimes H_1(M)_{\textrm{Tors}}\to \mathbb{Q}/\mathbb{Z}

    If the government wants to introduce a real revolution in law and order, it should devolve powers and budgets for all criminal justice and emergency services to PCCs

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    Will Tanner argues that if the Prime Minister is serious about his ‘tough but intelligent’ approach to crime and justice then resources should be directed to what is proven to work. The astonishing success of the Violence Reduction Unit (VRU) in Glasgow is just such a project. Only through such localism could initiatives like the VRU become the norm

    Scaled-free objects II

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    This work creates two categories of "array-weighted sets" for the purposes of constructing universal matrix-normed spaces and algebras. These universal objects have the analogous universal property to the free vector space, lifting maps completely bounded on a generation set to a completely bounded linear map of the matrix-normed space. Moreover, the universal matrix-normed algebra is used to prove the existence of a free product for matrix-normed algebras using algebraic methods.Comment: 46 pages. Version 4 fixed a few minor typos. Version 3 added matricial completion; fixed an arithmetic error in Example 3.5.10. Version 2 added a preliminaries section on weighted sets and matricial Banach spaces, incorporating much of "Matricial Banach spaces" in summary; fixed a domain issue in Lemma 3.3.2; simplified Examples 3.5.10 and 4.11; added more proofs to Sections 4 and
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