Around the Lie correspondence for complete Kac–Moody groups and Gabber–Kac simplicity
Annales de l'Institut Fourier, Volume 69 (2019) no. 6, pp. 2519-2576

Let k be a field and A be a generalised Cartan matrix, and let 𝔊 A (k) be the corresponding minimal Kac–Moody group of simply connected type over k. Consider the completion 𝔊 A pma (k) of 𝔊 A (k) introduced by O. Mathieu and G. Rousseau, and let 𝔘 A ma+ (k) denote the unipotent radical of the Borel subgroup of 𝔊 A pma (k). In this paper, we exhibit a functorial dependence of the groups 𝔘 A ma+ (k) and 𝔊 A pma (k) on their Lie algebra. We also provide several contributions to fundamental questions in the general theory of maximal Kac–Moody groups: (non-)Gabber–Kac simplicity over certain finite fields, (non-)density of a minimal Kac–Moody group in its Mathieu–Rousseau completion, (non-)linearity of maximal pro-p subgroups, and the isomorphism problem.

Soit 𝔊 A (k) le groupe de Kac–Moody minimal simplement connexe associé à un corps k et à une matrice de Cartan généralisée A. On note 𝔊 A pma (k) la complétion de 𝔊 A (k) introduite par O. Mathieu et G. Rousseau, et 𝔘 A ma+ (k) le radical unipotent du sous-groupe de Borel de 𝔊 A pma (k). Dans cet article, nous mettons en évidence une dépendance fonctorielle des groupes 𝔘 A ma+ (k) et 𝔊 A pma (k) en leur algèbre de Lie. Nous apportons en outre plusieurs contributions à certaines questions fondamentales de la théorie générale des groupes de Kac–Moody maximaux : (non-)densité du groupe de Kac–Moody minimal dans sa complétion de Mathieu–Rousseau, (non-)Gabber–Kac simplicité sur certains corps finis, (non-)linéarité des sous-groupes pro-p maximaux, et problème d’isomorphisme.

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DOI: 10.5802/aif.3301
Classification: 20G44, 20E42, 20E18
Keywords: Kac–Moody groups, Lie correspondence, Gabber–Kac simplicity, Linearity problem, Isomorphism problem
Mots-clés : Groupes de Kac–Moody, Correspondance de Lie, Simplicité au sens de Gabber–Kac, Problème de linéarité, Problème d’isomorphisme

Marquis, Timothée  1

1 FAU Erlangen-Nuernberg Department Mathematik Cauerstrasse 11 91058 Erlangen (Germany)
License: CC-BY-ND 4.0
Copyrights: The authors retain unrestricted copyrights and publishing rights
Marquis, Timothée. Around the Lie correspondence for complete Kac–Moody groups and Gabber–Kac simplicity. Annales de l'Institut Fourier, Volume 69 (2019) no. 6, pp. 2519-2576. doi: 10.5802/aif.3301
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[1] Abramenko, Peter; Brown, Kenneth S. Buildings. Theory and applications, Graduate Texts in Mathematics, 248, Springer, 2008, xxii+747 pages | Zbl

[2] Capdeboscq, Inna; Rémy, Bertrand On some pro-p groups from infinite-dimensional Lie theory, Math. Z., Volume 278 (2014) no. 1-2, pp. 39-54 | MR | DOI | Zbl

[3] Caprace, Pierre-Emmanuel “Abstract” homomorphisms of split Kac–Moody groups, Mem. Am. Math. Soc., Volume 198 (2009) no. 924, xvi+84 pages | MR | Zbl

[4] Caprace, Pierre-Emmanuel; Reid, Colin D.; Willis, George A. Locally normal subgroups of totally disconnected groups. Part II: Compactly generated simple groups, Forum Math. Sigma, Volume 5 (2017), e12, 89 pages | MR | DOI | Zbl

[5] Caprace, Pierre-Emmanuel; Rémy, Bertrand Simplicity and superrigidity of twin building lattices, Invent. Math., Volume 176 (2009) no. 1, pp. 169-221 | MR | DOI | Zbl

[6] Caprace, Pierre-Emmanuel; Stulemeijer, Thierry Totally disconnected locally compact groups with a linear open subgroup, Int. Math. Res. Not. (2015) no. 24, pp. 13800-13829 | MR | DOI | Zbl

[7] Carbone, Lisa; Chung, Sjuvon; Cobbs, Leigh; McRae, Robert; Nandi, Debajyoti; Naqvi, Yusra; Penta, Diego Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits, J. Phys. A, Math. Gen., Volume 43 (2010) no. 15, 155209, 30 pages | MR | DOI | Zbl

[8] Carbone, Lisa; Garland, Howard Existence of lattices in Kac–Moody groups over finite fields, Commun. Contemp. Math., Volume 5 (2003) no. 5, pp. 813-867 | MR | DOI | Zbl

[9] Dixon, John D.; du Sautoy, Marcus P. F.; Mann, Avinoam; Segal, Dan Analytic pro-p groups, Cambridge Studies in Advanced Mathematics, 61, Cambridge University Press, 1999, xviii+368 pages | MR | DOI | Zbl

[10] Hainke, Guntram; Köhl, Ralf; Levy, Paul Generalized spin representations, Münster J. Math., Volume 8 (2015) no. 1, pp. 181-210 (With an appendix by Max Horn and Ralf Köhl) | MR | Zbl

[11] Kac, Victor G. Infinite-dimensional Lie algebras, Cambridge University Press, 1990, xxii+400 pages | Zbl

[12] Kang, Seok-Jin; Melville, Duncan J. Rank 2 symmetric hyperbolic Kac–Moody algebras, Nagoya Math. J., Volume 140 (1995), pp. 41-75 | MR | DOI | Zbl

[13] Kumar, Shrawan Kac–Moody groups, their flag varieties and representation theory, Progress in Mathematics, 204, Birkhäuser, 2002, xvi+606 pages | MR | Zbl

[14] Lyndon, Roger C.; Schupp, Paul E. Combinatorial group theory, Classics in Mathematics, Springer, 2001, xiv+339 pages (Reprint of the 1977 edition) | Zbl

[15] Marquis, Timothée Topological Kac–Moody groups and their subgroups, Université Catholique de Louvain (Belgium) (2013) (Ph. D. Thesis) | Zbl

[16] Marquis, Timothée Abstract simplicity of locally compact Kac-Moody groups, Compos. Math., Volume 150 (2014) no. 4, pp. 713-728 | MR | DOI | Zbl

[17] Marquis, Timothée An introduction to Kac–Moody groups over fields, EMS Textbooks in Mathematics, European Mathematical Society, 2018, 343 pages | MR | DOI | Zbl

[18] Mathieu, Olivier Construction du groupe de Kac–Moody et applications, C. R. Math. Acad. Sci. Paris, Volume 306 (1988) no. 5, pp. 227-230 | MR | Zbl

[19] Moody, Robert A simplicity theorem for Chevalley groups defined by generalized Cartan matrices (preprint)

[20] Morita, Jun Root strings with three or four real roots in Kac-Moody root systems, Tôhoku Math. J., Volume 40 (1988) no. 4, pp. 645-650 | MR | DOI | Zbl

[21] Mühlherr, Bernhard Locally split and locally finite twin buildings of 2-spherical type, J. Reine Angew. Math., Volume 511 (1999), pp. 119-143 | MR | DOI | Zbl

[22] Mühlherr, Bernhard Twin buildings, Tits buildings and the model theory of groups (Würzburg, 2000) (London Mathematical Society Lecture Note Series), Volume 291, Cambridge University Press, 2002, pp. 103-117 | MR | DOI | Zbl

[23] Nikolov, Nikolay; Segal, Dan On finitely generated profinite groups. I. Strong completeness and uniform bounds, Ann. Math., Volume 165 (2007) no. 1, pp. 171-238 | MR | DOI | Zbl

[24] Rémy, Bertrand Groupes de Kac–Moody déployés et presque déployés, Astérisque, 277, Société Mathématique de France, 2002, viii+348 pages | Zbl

[25] Rémy, Bertrand Topological simplicity, commensurator super-rigidity and non-linearities of Kac–Moody groups, Geom. Funct. Anal., Volume 14 (2004) no. 4, pp. 810-852 (With an appendix by P. Bonvin) | MR | DOI | Zbl

[26] Rémy, Bertrand; Ronan, Mark Topological groups of Kac–Moody type, right-angled twinnings and their lattices, Comment. Math. Helv., Volume 81 (2006) no. 1, pp. 191-219 | MR | DOI | Zbl

[27] Riehm, Carl The congruence subgroup problem over local fields, Am. J. Math., Volume 92 (1970), pp. 771-778 | MR | DOI | Zbl

[28] Rousseau, Guy Groupes de Kac–Moody déployés sur un corps local, II Masures ordonnées, Bull. Soc. Math. Fr., Volume 144 (2016) no. 4, pp. 613-692 | MR | DOI | Zbl

[29] Tits, Jacques Uniqueness and presentation of Kac–Moody groups over fields, J. Algebra, Volume 105 (1987) no. 2, pp. 542-573 | MR | DOI | Zbl

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