1,049 research outputs found

    The Regularity Problem for Lie Groups with Asymptotic Estimate Lie Algebras

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    We solve the regularity problem for Milnor's infinite dimensional Lie groups in the asymptotic estimate context. Specifically, let GG be a Lie group with asymptotic estimate Lie algebra g\mathfrak{g}, and denote its evolution map by evol ⁣:Ddom[evol]G\mathrm{evol}\colon \mathrm{D}\equiv \mathrm{dom}[\mathrm{evol}]\rightarrow G, i.e., DC0([0,1],g)\mathrm{D}\subseteq C^0([0,1],\mathfrak{g}). We show that evol\mathrm{evol} is CC^\infty-continuous on DC([0,1],g)\mathrm{D}\cap C^\infty([0,1],\mathfrak{g}) if and only if evol\mathrm{evol} is C0C^0-continuous on DC0([0,1],g)\mathrm{D}\cap C^0([0,1],\mathfrak{g}). We furthermore show that GG is k-confined for kN{lip,}k\in \mathbb{N}\sqcup\{\mathrm{lip},\infty\} if GG is constricted. (The latter condition is slightly less restrictive than to be asymptotic estimate.) Results obtained in a previous paper then imply that an asymptotic estimate Lie group GG is CC^\infty-regular if and only if it is Mackey complete, locally μ\mu-convex, and has Mackey complete Lie algebra - In this case, GG is CkC^k-regular for each kN1{lip,}k\in \mathbb{N}_{\geq 1}\sqcup\{\mathrm{lip},\infty\} (with ``smoothness restrictions'' for klipk\equiv\mathrm{lip}), as well as C0C^0-regular if GG is even sequentially complete with integral complete Lie algebra.Comment: 27 pages. Version as published at Indagationes Mathematicae (title refined; presentation improved; proof of Lemma 9 revised

    A Characterization of Invariant Connections

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    Given a principal fibre bundle with structure group SS, and a fibre transitive Lie group GG of automorphisms thereon, Wang's theorem identifies the invariant connections with certain linear maps ψ ⁣:gs\psi\colon \mathfrak{g}\rightarrow \mathfrak{s}. In the present paper, we prove an extension of this theorem which applies to the general situation where GG acts non-transitively on the base manifold. We consider several special cases of the general theorem, including the result of Harnad, Shnider and Vinet which applies to the situation where GG admits only one orbit type. Along the way, we give applications to loop quantum gravity

    Regularity of Lie Groups

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    We solve the regularity problem for Milnor's infinite dimensional Lie groups in the C0C^0-topological context, and provide necessary and sufficient regularity conditions for the standard setting (CkC^k-topology). We prove that the evolution map is C0C^0-continuous on its domain iff\textit{iff}\hspace{1pt} the Lie group GG is locally μ\mu-convex. We furthermore show that if the evolution map is defined on all smooth curves, then GG is Mackey complete - This is a completeness condition formulated in terms of the Lie group operations that generalizes Mackey completeness as defined for locally convex vector spaces. Then, under the presumption that GG is locally μ\mu-convex, we show that each CkC^k-curve, for kN1{lip,}k\in \mathbb{N}_{\geq 1}\sqcup\{\mathrm{lip},\infty\}, is integrable (contained in the domain of the evolution map) iff\textit{iff}\hspace{1pt} GG is Mackey complete and k\mathrm{k}-confined. The latter condition states that each CkC^k-curve in the Lie algebra g\mathfrak{g} of GG can be uniformly approximated by a special type of sequence consisting of piecewise integrable curves - A similar result is proven for the case k0k\equiv 0; and we provide several mild conditions that ensure that GG is k\mathrm{k}-confined for each kN{lip,}k\in \mathbb{N}\sqcup\{\mathrm{lip},\infty\}. We finally discuss the differentiation of parameter-dependent integrals in the standard topological context. In particular, we show that if the evolution map is well defined and continuous on Ck([0,1],g)C^k([0,1],\mathfrak{g}) for kN{}k\in \mathbb{N}\sqcup\{\infty\}, then it is smooth thereon iff\textit{iff}\hspace{1pt} g\mathfrak{g} is \hspace{0.2pt} Mackey complete for kN1{}k\in \mathbb{N}_{\geq 1}\sqcup\{\infty\} /\hspace{1pt}/\hspace{1pt} integral complete for k0k\equiv 0. This result is obtained by calculating the directional derivatives explicitly - recovering the standard formulas that hold in the Banach case.Comment: 72 pages. Revised version: notations simplified; oversights corrected; example added to Sect. 3.5.2; Lemma 40 (now Lemma 13) shifted into Sect. 3.5.4; Lipschitz case added to Lemma 23 (now Lemma 24); proof of Lemma 25 (now Lemma 26) revised; Proposition 6 correcte

    Decompositions of Analytic 1-Manifolds

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    In a previous paper, connected analytic 1-dimensional submanifolds with boundary have been classified w.r.t. their symmetry under a given regular Lie group action on an analytic manifold. It was shown that each such submanifold is either free or analytically diffeomorphic to the unit circle or some interval via the exponential map. In this paper, we show that each free connected analytic 1-submanifold naturally splits into symmetry free segments, mutually and uniquely related by the group action. This is proven under the assumption that the action is non-contractive, which is even less restrictive than regularity.Comment: 25 page

    Heterogeneity and Evolutionary Change - Empirical Conception, Findings and Unresolved Issues

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    In this position paper we deal with the conception of heterogeneity as both the force and the result of evolutionary change. We ask, how this heterogeneity can be measured empirically and how we can get a measure which allows to get a broad comparable empirical account especially on several levels of aggregation. Based on this discussion we suggest that for several questions the measures of total factor productivity (TFP) and local changes of TFP seem to be acceptable candidates for measuring heterogeneity and its dynamics. Examples out of a number of empirical investigations applying this measures show how interesting empirical facts about evolutionary change on several levels of aggregation can be detected. The paper concludes by raising a number of unresolved issues mainly related to the question about the relationship between evolutionary dynamics on several levels of aggregation.

    Recent Trends in the Research on National Innovation Systems

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    In this paper, we give an overview on recent developments in the research on national innovation systems (NIS). Essentially, we identify three development lines of the concept. These are policy-oriented studies that frequently combine the NIS approach with the terminology of corporate benchmarking, contributions to formalize the concept of NIS through descriptive or analytical models, and NIS studies of countries beyond the group of highly industrialized economies. It follows from the analysis of these research trends that the concept has developed in distinctive directions. In international comparisons of innovation systems, heterogeneity in the structure of the systems is only marginally taken into account, an aspect that may reduce the explanatory power of such system-level comparisons. Contrary to this, historically grown organizational and institutional structures are extensively described and considered in NIS studies of industrializing countries, a characteristic which ties up with early studies of national innovation systems.innovation, national innovation systems, comparative studies
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