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Simply transitive NIL-affine actions of solvable Lie groups

  • Jonas DerĂ© and Marcos Origlia EMAIL logo
Published/Copyright: July 17, 2021

Abstract

Every simply connected and connected solvable Lie group đș admits a simply transitive action on a nilpotent Lie group đ» via affine transformations. Although the existence is guaranteed, not much is known about which Lie groups đș can act simply transitively on which Lie groups đ». So far, the focus was mainly on the case where đș is also nilpotent, leading to a characterization depending only on the corresponding Lie algebras and related to the notion of post-Lie algebra structures. This paper studies two different aspects of this problem. First, we give a method to check whether a given action ρ:G→Aff⁥(H) is simply transitive by looking only at the induced morphism φ:g→aff⁥(h) between the corresponding Lie algebras. Secondly, we show how to check whether a given solvable Lie group đș acts simply transitively on a given nilpotent Lie group đ», again by studying properties of the corresponding Lie algebras. The main tool for both methods is the semisimple splitting of a solvable Lie algebra and its relation to the algebraic hull, which we also define on the level of Lie algebras. As an application, we give a full description of the possibilities for simply transitive actions up to dimension 4.

MSC 2010: 22E25; 17B30

Award Identifier / Grant number: G.0F93.17N

Award Identifier / Grant number: DP190100317

Funding statement: The first author is supported by a postdoctoral fellowship of the Research Foundation – Flanders (FWO). The second author was supported by the Research Foundation – Flanders (FWO Project G.0F93.17N), CONICET (Argentina) and ARC (Australia) DP190100317.

Acknowledgements

Most of the work has been written during the post-doctoral position at KU Leuven, Campus Kulak Kortrijk of the second named author. He is grateful to the department for the hospitality.

  1. Communicated by: Anna Wienhard

References

[1] A. Andrada, M. L. Barberis, I. G. Dotti and G. P. Ovando, Product structures on four dimensional solvable Lie algebras, Homology Homotopy Appl. 7 (2005), no. 1, 9–37. 10.4310/HHA.2005.v7.n1.a2Search in Google Scholar

[2] L. Auslander, Simply transitive groups of affine motions, Amer. J. Math. 99 (1977), no. 4, 809–826. 10.2307/2373867Search in Google Scholar

[3] Y. Benoist, Une nilvariĂ©tĂ© non affine, C. R. Acad. Sci. Paris SĂ©r. I Math. 315 (1992), no. 9, 983–986. 10.4310/jdg/1214456006Search in Google Scholar

[4] Y. Benoist, Une nilvariĂ©tĂ© non affine, J. Differential Geom. 41 (1995), no. 1, 21–52. 10.4310/jdg/1214456006Search in Google Scholar

[5] Y. Benoist and K. Dekimpe, The uniqueness of polynomial crystallographic actions, Math. Ann. 322 (2002), no. 3, 563–571. 10.1007/s002080200005Search in Google Scholar

[6] A. Borel, Linear Algebraic Groups, 2nd ed., Grad. Texts in Math. 126, Springer, New York, 1991. 10.1007/978-1-4612-0941-6Search in Google Scholar

[7] D. Burde, Affine structures on nilmanifolds, Internat. J. Math. 7 (1996), no. 5, 599–616. 10.1142/S0129167X96000323Search in Google Scholar

[8] D. Burde, K. Dekimpe and S. Deschamps, Affine actions on nilpotent Lie groups, Forum Math. 21 (2009), no. 5, 921–934. 10.1515/FORUM.2009.045Search in Google Scholar

[9] D. Burde and F. Grunewald, Modules for certain Lie algebras of maximal class, J. Pure Appl. Algebra 99 (1995), no. 3, 239–254. 10.1016/0022-4049(94)00002-ZSearch in Google Scholar

[10] S. Console and A. Fino, On the de Rham cohomology of solvmanifolds, Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 10 (2011), no. 4, 801–818. 10.2422/2036-2145.2011.4.02Search in Google Scholar

[11] W. A. de Graaf, Computation with Linear Algebraic Groups, Monogr. Res. Notes Math., CRC Press, Boca Raton, 2017. 10.1201/9781315120140Search in Google Scholar

[12] K. Dekimpe, Semi-simple splittings for solvable Lie groups and polynomial structures, Forum Math. 12 (2000), no. 1, 77–96. 10.1515/form.1999.030Search in Google Scholar

[13] J. Deré, Nil-affine crystallographic actions of virtually polycyclic groups, preprint (2019), https://arxiv.org/abs/1810.11290. 10.1007/s00031-021-09673-wSearch in Google Scholar

[14] N. Dungey, A. F. M. ter Elst and D. W. Robinson, Analysis on Lie Groups with Polynomial Growth, Progr. Math. 214, BirkhÀuser Basel, 2003. 10.1007/978-1-4612-2062-6Search in Google Scholar

[15] J. E. Humphreys, Linear Algebraic Groups, Grad. Texts in Math., Springer, New York, 1981. Search in Google Scholar

[16] H. Kasuya, Algebraic hulls of solvable groups and exponential iterated integrals on solvmanifolds, Geom. Dedicata 162 (2013), 263–270. 10.1007/s10711-012-9725-1Search in Google Scholar

[17] H. Kasuya, Minimal models, formality, and hard Lefschetz properties of solvmanifolds with local systems, J. Differential Geom. 93 (2013), no. 2, 269–297. 10.4310/jdg/1361800867Search in Google Scholar

[18] H. Kim, Complete left-invariant affine structures on nilpotent Lie groups, J. Differential Geom. 24 (1986), no. 3, 373–394. 10.4310/jdg/1214440553Search in Google Scholar

[19] J. Milnor, On fundamental groups of complete affinely flat manifolds, Adv. Math. 25 (1977), no. 2, 178–187. 10.1016/0001-8708(77)90004-4Search in Google Scholar

[20] M. S. Raghunathan, Discrete Subgroups of Lie Groups, Ergeb. Math. Grenzgeb. (3) 68, Springer, New York, 1972. 10.1007/978-3-642-86426-1Search in Google Scholar

Received: 2020-05-08
Revised: 2021-04-12
Published Online: 2021-07-17
Published in Print: 2021-09-01

© 2021 Walter de Gruyter GmbH, Berlin/Boston

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