426 research outputs found

    More Set-theory around the weak Freese-Nation property

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    In this paper, we introduce a very weak square principle which is even weaker than the similar principle introduced by Foreman and Magidor. A characterization of this principle is given in term of sequences of elementary submodels of H(\chi). This is used in turn to prove a characterization of kappa-Freese-Nation property under the very weak square principle and a weak variant of the Singular Cardinals Hypothesis. A typical application of this characterization shows that under 2^{\aleph_0}<\aleph_\omega and our very weak square for \aleph_\omega, the partial ordering [omega_\omega]^{<\omega} (ordered by inclusion) has the aleph_1-Freese-Nation property. On the other hand we show that, under Chang's Conjecture for \aleph_\omega the partial ordering above does not have the aleph_1-Freese-Nation property. Hence we obtain the independence of our characterization of the kappa-Freese-Nation property and also of the very weak square principle from ZFC

    The New Hampshire, Vol. 33, No. 10 (Dec. 16, 1942)

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    An independent student produced newspaper from the University of New Hampshire

    The BG News April 12, 1989

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    The BGSU campus student newspaper April 12, 1989. Volume 71 - Issue 117https://scholarworks.bgsu.edu/bg-news/5931/thumbnail.jp

    The Chronicle [March 30, 2009]

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    The Chronicle, March 30, 2009https://repository.stcloudstate.edu/chron/1703/thumbnail.jp

    Visible and dark matter from a first-order phase transition in a baryon-symmetric universe

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    The similar cosmological abundances observed for visible and dark matter suggest a common origin for both. By viewing the dark matter density as a dark-sector asymmetry, mirroring the situation in the visible sector, we show that the visible and dark matter asymmetries may have arisen simultaneously through a first-order phase transition in the early universe. The dark asymmetry can then be equal and opposite to the usual visible matter asymmetry, leading to a universe that is symmetric with respect to a generalised baryon number. We present both a general structure, and a precisely defined example of a viable model of this type. In that example, the dark matter is atomic as well as asymmetric, and various cosmological and astrophysical constraints are derived. Testable consequences for colliders include a Z' boson that couples through the B-L charge to the visible sector, but also decays invisibly to dark sector particles. The additional scalar particles in the theory can mix with the standard Higgs boson and provide other striking signatures.Comment: 26 pages, comments and references added, JCAP versio

    Flyer News, Vol. 61, No. 24

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    Student-run newspaper of the University of Dayton

    String Cosmology - Large-Field Inflation in String Theory

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    This is a short review of string cosmology. We wish to connect string-scale physics as closely as possible to observables accessible to current or near-future experiments. Our possible best hope to do so is a description of inflation in string theory. The energy scale of inflation can be as high as that of Grand Unification (GUT). If this is the case, this is the closest we can possibly get in energy scales to string-scale physics. Hence, GUT-scale inflation may be our best candidate phenomenon to preserve traces of string-scale dynamics. Our chance to look for such traces is the primordial gravitational wave, or tensor mode signal produced during inflation. For GUT-scale inflation this is strong enough to be potentially visible as a B-mode polarization of the cosmic microwave background (CMB). Moreover, a GUT-scale inflation model has a trans-Planckian excursion of the inflaton scalar field during the observable amount of inflation. Such large-field models of inflation have a clear need for symmetry protection against quantum corrections. This makes them ideal candidates for a description in a candidate fundamental theory like string theory. At the same time the need of large-field inflation models for UV completion makes them particularly susceptible to preserve imprints of their string-scale dynamics in the inflationary observables, the spectral index nsn_s and the fractional tensor mode power rr. Hence, we will focus this review on axion monodromy inflation as a mechanism of large-field inflation in string theory.Comment: 34 pages, 1 figure, LaTeX, v2: typos fixed, 3 references added, agrees with published version in "Perspectives in String Phenomenology" and "International Journal of Modern Physics A

    Maine Campus April 16 1942

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    The Montana Kaimin, November 30, 1937

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    Student newspaper of the University of Montana, Missoula.https://scholarworks.umt.edu/studentnewspaper/2667/thumbnail.jp

    Maine Campus February 04 1932

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