منابع مشابه
On Infinite Unramified Extensions
Let k be a number field. A natural question is: Does k admit an infinite unramified extension? The answer is no, if the root discriminant of k is less than Odlyzko’s bounds. The answer is yes, if k fails the test of Golod-Shafarevic for a prime number p. In that case, we know that there exists an infinite unramified p-extension L over k. But generally it is fairly difficult to determin whether ...
متن کاملExtensions to Basu’s theorem, factorizations, and infinite divisibility
We define a notion of approximate sufficiency and approximate ancillarity and show that such statistics are approximately independent pointwise under each value of the parameter. We do so without mentioning the somewhat nonintuitive concept of completeness, thus providing a more transparent version of Basu’s theorem. Two total variation inequalities are given, which we call approximate Basu the...
متن کاملThe Nielsen-Thurston Classification Theorem
Overview: The Nielsen-Thurston Classification Theorem asserts that every element of MCG(Sg) (g ≥ 2) exhibits one of three types of simple behavior. It either has finite order, fixes a nonempty set of of isotopy classes of essential, simple closed curves (reducible), or stretches along a pair of transverse measured foliations in an area-preserving way (pseduo-Anosov). Bers’ strategy for proving ...
متن کاملA Proof of the Nielsen-Ninomiya Theorem
The Nielsen-Ninomiya theorem asserts the impossibility of constructing lattice models of non-selfinteracting chiral fermions. A new proof is given here. This proof fills a technical gap in the two proofs presented by the authors of the theorem. It also serves as prelude to an investigation of the chiral properties of the general lattice model.
متن کاملOn extensions of Myers' theorem
Let M be a compact Riemannian manifold and h a smooth function on M. Let h (x) = inf jvj=1 (Ric x (v; v) ? 2Hess(h) x (v; v)). Here Ric x denotes the Ricci curvature at x and Hess(h) is the Hessian of h. Then M has nite fundamental group if h ? h < 0. Here h =: + 2L rh is the Bismut-Witten Laplacian. This leads to a quick proof of recent results on extension of Myers' theorem to mani-folds with...
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ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 1986
ISSN: 0002-9939
DOI: 10.1090/s0002-9939-1986-0840629-2