Abstract
We show that conformal mappings between the Engel groups are CR or anti-CR mappings. This reduces the determination of conformal mappings to a problem in the theory of several complex analysis. The result about the group of CR automorphisms is used to determine the identity component of the group of conformal mappings on the Engel group.
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Korányi A, Reimann H M. Foundations for the theory of quasiconformal mappings on the Heisenberg group. Adv Math, 111(1): 1–87 (1995)
Mostow G D. Strong rigidity of locally symmetric spaces. In: Annals of Mathematics Studies, No. 78. Princeton: Princeton University Press; Tokyo: University of Tokyo Press, 1973
Capogna L, Cowling M. Conformality and Q-harmonicity in Carnot groups. Duke Math J, 135(3): 455–479 (2006)
Gromov M. Carnot-Carathéodory spaces seen from within. In: Sub-Riemannian geometry, Progr Math, 144. Basel: Birkhäuser, 1996, 79–323
Pansu P. Métriques de Carnot-Carathéodory et quasiisométries des espacies symétriques de rang un (in French). Ann Math, 129: 1–60 (1989)
Vodop’yanov S K. On the differentiability of mappings of Sobolev classes on the Carnot group (in Russian). Mat Sb, 194(6): 67–86 (2003); translation in Sb Math, 194(5–6): 857–877 (2003)
Korányi A, Reimann H M. Quasiconformal mappings on the Heisenberg group. Invent Math, 80(2): 309–338 (1985)
Capogna L. Regularity of quasi-linear equations in the Heisenberg group. Comm Pure Appl Math, 50(9): 867–889 (1997)
Cowling M, De Mari F, Korányi A, et al. Contact and conformal maps in parabolic geometry I. Geom Dedicata, 111: 65–86 (2005)
Müller D. Another example in the solvability theory of PDO’s with double characteristics. Comm Partial Differential Equations, 20(11–12): 2165–2186 (1995)
Meylan F, Mir N, Zaitsev D. Holomorphic extension of smooth CR-mappings between real-analytic and real-algebraic CR-manifolds. Asian J Math, 7(4): 493–509 (2003)
Beloshapka V K, Ežov V V and Schmals G. Vitushkin’s germ theorem for CR-manifolds of Engel type (in Russian). Tr Mat Inst Steklova, 253: 7–13 (2006); translation in Proc Steklov Inst Math, 253(2): 1–7 (2006)
Chow W L. Über Systeme von linearen partiellen differentialgleichungen erster ordnung (in German). Math Ann, 117: 98–105 (1939)
Nagel A, Stein E M, Wainger S. Balls and metrics defined by vector fields I, Basic properties. Acta Math, 155(1–2): 103–147 (1985)
Pansu P. Quasiisométries des variétés de courbure négative. PhD Thesis. Paris: University of Paris VII, 1987
Warner FW. Foundations of Differentiable Manifolds and Lie Groups. Corrected reprint of the 1971 edition. Graduate Texts in Mathematics, Vol. 94. New York-Berlin: Springer-Verlag, 1983
Balogh Z M, Holopainen I, Tyson J T. Singular solutions, homogeneous norms, and quasiconformal mappings in Carnot groups. Math Ann, 324(1): 159–186 (2002)
Wang W. Canonical contact forms on spherical CR manifolds. J Eur Math Soc, 5: 245–273 (2003)
Wang W. The Teichmüller distance on the space of spherical CR structures. Sci China Ser A, 49(11): 1523–1538 (2006)
Margulis G A, Mostow G D. The differential of a quasi-conformal mapping of a Carnot-Carathéodory space. Geom Funct Anal, 5(2): 402–433 (1995)
Wu Q Y. 1-quasiconformal mappings on a (2, 2)-type quadric. Appl Math J Chinese Univ Ser B, 24(1): 65–75 (2009)
Magnani V. Differentiability and area formula on stratified Lie groups (English summary). Houston J Math, 27(2): 297–323 (2001)
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Dedicated to Professor ZHONG TongDe on the occasion of his 80th birthday
This work was supported by National Natural Science Foundation of China (Grant No. 10871172)
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Wu, Q., Wang, W. Conformal mappings and CR mappings on the Engel group. Sci. China Ser. A-Math. 52, 2759–2773 (2009). https://doi.org/10.1007/s11425-009-0177-5
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DOI: https://doi.org/10.1007/s11425-009-0177-5