Abstract
We consider the conjugation-action of an arbitrary upper-block parabolic subgroup of the general linear group on the variety of nilpotent matrices in its Lie algebra. Lie-theoretically, it is natural to wonder about the number of orbits of this action. We translate the setup to a representation-theoretic one and obtain a finiteness criterion which classifies all actions with only a finite number of orbits over an arbitrary infinite field. These results are applied to commuting varieties and nested punctual Hilbert schemes.
Similar content being viewed by others
References
A. Aitken, H. W. Turnbull, An Introduction to the Theory of Canonical Matrices, Dover, New York, 1961.
I. Assem, D. Simson, A. Skowroński, Elements of the Representation Theory of Associative Algebras, Vol. 1, Techniques of Representation Theory, London Mathematical Society Student, Vol. 65, Cambridge University Press, Cambridge, 2006.
K. Bongartz, P. Gabriel, Covering spaces in representation-theory, Invent. Math. 65 (1981/82), no. 3, 331–378.
M. Boos, Finite parabolic conjugation on varieties of nilpotent matrices, Algebr. Represent. Theory 17 (2014), no. 6, 1657–1682.
M. Boos, Staircase algebras and graded nilpotent pairs, J. Pure Appl. Algebra 221 (2017), no. 8, 2032–2052.
T. Brüstle, L. Hille, Finite, tame, and wild actions of parabolic subgroups in GL(V) on certain unipotent subgroups. J. Algebra 226 (2000), 347–380.
M. Bulois, L. Evain, Nested punctual hilbert schemes and commuting varieties of parabolic subalgebras, J. Lie Theory 26 (2016), no. 2, 497–533.
J. Cheah, Cellular decompositions for nested Hilbert schemes of points, Pacific J. Math. 183 (1998), no. 1, 39–90.
V. Dlab, C. M. Ringel, The module theoretical approach to quasi-hereditary algebras. in: Representations of Algebras and Related Topics, London Math. Soc. Lecture Note Ser., Vol. 168, Cambridge University Press, Cambridge, 1992, pp. 200–224.
P. Gabriel, Unzerlegbare Darstellungen. I, Manuscripta Math. 6 (1972), 71–103, correction, ibid., 309.
P. Gabriel, The universal cover of a representation-finite algebra, in: Representations of Algebras (Puebla, 1980), Lecture Notes in Math., Vol. 903, Springer, Berlin, 1981, pp. 68–105.
C. Geiss, B. Leclerc, J. Schröer, Quivers with relations for symmetrizable cartan matrices i: Foundations, Invent. Math. 209 (2017), no. 1, 61–158.
R. Goddard, S. M. Goodwin, On commuting varieties of parabolic subalgebras, J. Pure Appl. Algebra 222 (2018), no. 3, 481–507.
S. M. Goodwin, G. Röhrle, On commuting varieties of nilradicals of borel subalgebras of reductive lie algebras, Proc. Edinburgh Math. Soc. (2) 58 (2015), 169–181.
D. Happel, D. Vossieck, Minimal algebras of infinite representation type with pre-projective component, Manuscripta Math. 42 (1983), no. 2-3, 221–243.
L. Hille, G. Röhrle, A classification of parabolic subgroups of classical groups with a finite number of orbits on the unipotent radical, Transform. Groups 4 (1999), no. 1, 35–52.
M. E. C. Jordan, Traité des Substitutions et des Équations Algébriques, Les Grands Classiques Gauthier-Villars, Éditions Jacques Gabay, Sceaux, 1989.
A. G. Keeton, Commuting Varieties Associated with Symmetric Pairs, PhD thesis, University of California, San Diego, 1996.
S. H. Murray, Conjugacy classes in maximal parabolic subgroups of general linear groups, J. Algebra 233 (2000), 135–155.
H. Nakajima, Lectures on Hilbert Schemes of Points on Surfaces, University Lecture Series, Vol. 18, American Mathematical Society, 1999.
A. Premet, Nilpotent commuting varieties of reductive lie algebras, Invent. Math. 154 (2003), no. 3, 653–683.
R. W. Richardson, Commuting varieties of semisimple lie algebras and algebraic groups, Compositio Math. 38 (1979), no. 3, 311–327.
C. M. Ringel, Iyama’s finiteness theorem via strongly quasi-hereditary algebras, J. Pure Appl. Algebra 214 (2010), no. 9, 1687–1692.
G. Röhrle, On the modality of parabolic subgroups of linear algebraic groups, Manuscripta Math. 98 (1999), no. 1, 9–20.
J-P. Serre, Espaces fibrés algébriques, Séminaire Claude Chevalley 3 (1958), 1–37.
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by Ruhr-University Bochum; benefited from a one month “professeur invité” position at University of Saint-Étienne.
Supported by Université Jean Monnet, Labex MILYON/ANR-10-LABX-0070 and ANR Grant GeoLie/ANR-15-CE40-0012.
Rights and permissions
About this article
Cite this article
BOOS, M., BULOIS, M. PARABOLIC CONJUGATION AND COMMUTING VARIETIES. Transformation Groups 24, 951–986 (2019). https://doi.org/10.1007/s00031-018-9507-4
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00031-018-9507-4