Abstract
Based on the parametrization proposed in [HH85], K.-H. Neeb investigated in [Ne91] the globality of a certain one-parameter family of Lorentzian cones in the universal covering group\(\widetilde{Sl}(2)\) of SI(2). In this article, we use the Pontrjagin Maximum Principle in order to obtain an explicit description of the semigroups generated by these cones, resp., to find conal curves which return to the identity. Furthermore we improve the description of the exponential function of\(\widetilde{Sl}(2)\).
An adequate general framework should be that of J. Hilgert in [Hi92] who investigated the globality resp. controllability of pointed generating conesC which are invariant under the adjoint action of a compact subgroupK that comes from an Iwasawa decompositionG=NAK.
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[HH85] Hofmann, K.H., and J. Hilgert,Old and New on Sl(2), Manuscripta Math.54 (1985), 17–52.
[Hi92] Hilgert, J.,Controllability on real reductive Lie-groups, Math. Zeitschrift209 (1992), 463–466.
[Mi91] Mittenhuber, D.,Lie-Gruppen, Kontrolltheorie und das Maximumprinzip, Seminar Sophus Lie Darmstadt Erlangen Greifswald Leipzig1 (1991), 185–192.
[Ne91] Neeb, K.-H.,Semigroups in the Universal Covering Group of SL(2), Semigroup Forum43 (1991), 33–43.
[Po62] Pontrjagin, L.S., “Mathematical Theory of optimal Processes,” Wiley Interscience, 1962.
[Su83] Sussmann, H.J.,Lie Brackets, Real Analyticity and Geometric Control, in R.W. Brockett, R.S. Milman and H.J. Sussmann, Editors, “Differential Geometric Control Theory,” S.1–116, Birkhäuser, Boston, 1983.
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Communicated by K. H. Hofmann
supported by a DFG-grant
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Mittenhuber, D. Semigroups in the simply connected covering of SL(2). Semigroup Forum 46, 379–387 (1993). https://doi.org/10.1007/BF02573580
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DOI: https://doi.org/10.1007/BF02573580