Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-20T06:56:41.107Z Has data issue: false hasContentIssue false

Minimal rational curves on generalized Bott–Samelson varieties

Published online by Cambridge University Press:  15 February 2021

Michel Brion
Affiliation:
Université Grenoble Alpes, 100 rue des Mathématiques, 38610Gières, [email protected]
S. Senthamarai Kannan
Affiliation:
Chennai Mathematical Institute, H1, SIPCOT IT Park, Siruseri, Kelambakkam603103, [email protected]

Abstract

We investigate families of minimal rational curves on Schubert varieties, their Bott–Samelson desingularizations, and their generalizations constructed by Nicolas Perrin in the minuscule case. In particular, we describe the minimal families on small resolutions of minuscule Schubert varieties.

Type
Research Article
Copyright
© The Author(s) 2021

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

To the memory of C. S. Seshadri

References

Atiyah, M. F., On analytic surfaces with double points, Proc. R. Soc. Lond. Ser. A 247 (1958), 237244.Google Scholar
Borel, A., Linear algebraic groups, second enlarged edition, Graduate Texts in Mathematics, vol. 26 (Springer, 1991).CrossRefGoogle Scholar
Bourbaki, N., Lie groups and Lie algebras: Chapters 4–6 (Springer, 2008).Google Scholar
Brion, M. and Fu, B., Minimal rational curves on wonderful group compactifications, J. Éc. polytech. Math. 2 (2015), 153170.CrossRefGoogle Scholar
Brion, M. and Kannan, S. S., Some combinatorial aspects of generalised Bott–Samelson varieties, Preprint (2019), arXiv:1910.06208.Google Scholar
Brion, M. and Polo, P., Generic singularities of certain Schubert varieties, Math. Z. 231 (1999), 301324.CrossRefGoogle Scholar
Brion, M., Samuel, P. and Uma, V., Lectures on the structure of algebraic groups and geometric applications (Hindustan Book Agency, New Dehli, 2013), https://www-fourier.univ-grenoble-alpes.fr/mbrion/chennai.pdf.CrossRefGoogle Scholar
Chary, B. N., Kannan, S. S. and Parameswaran, A. J., Automorphism group of a Bott–Samelson-Demazure-Hansen variety, Transform. Groups 20 (2015), 665698.CrossRefGoogle Scholar
Cohen, A. and Cooperstein, B., Line incidence systems from projective varieties, Proc. Amer. Math. Soc. 126 (1998), 20952102.CrossRefGoogle Scholar
Debarre, O., Higher-dimensional algebraic geometry, Universitext (Springer, 2001).CrossRefGoogle Scholar
Digne, F. and Michel, J., Representations of finite groups of Lie type (Cambridge University Press, 1991).CrossRefGoogle Scholar
Fulton, W., Intersection theory, Ergebnisse der Mathematik, vol. 2 (Springer, 1998).CrossRefGoogle Scholar
Fulton, W. and Woodward, C., On the quantum product of Schubert classes, J. Algebraic Geom. 13 (2004), 641661.CrossRefGoogle Scholar
Haboush, W., Lauritzen, N., Varieties of unseparated flags, in Linear algebraic groups and their representations, Contemporary Mathematics, vol. 153 (American Mathematical Society, 1993), 3557.CrossRefGoogle Scholar
Hong, J., Classification of smooth Schubert varieties in the symplectic Grassmannians, J. Korean Math. Soc. 52 (2015), 11091122.CrossRefGoogle Scholar
Hong, J. and Kwon, M., Rigidity of smooth Schubert varieties in a rational homogeneous manifold associated to a short root, Preprint (2019), arXiv:1907.09694.Google Scholar
Hong, J. and Mok, N., Characterization of smooth Schubert varieties in rational homogeneous manifolds of Picard number $1$, J. Algebraic Geom. 22 (2013), 333362.CrossRefGoogle Scholar
Humphreys, J. E., Introduction to Lie algebras and representation theory, Graduate Texts in Mathematics, vol. 9 (Springer, 1972).CrossRefGoogle Scholar
Hwang, J.-M., Mori geometry meets Cartan geometry: varieties of minimal rational tangents, in Proceedings of the International Congress of Mathematicians, Seoul 2014, vol. I (Kyung Moon SA, Seoul, 2014), 369394.Google Scholar
Hwang, J.-M. and Mok, N., Deformation rigidity of the rational homogeneous space associated to a long simple root, Ann. Sci. Éc. Norm. Supér. (4) 35 (2002), 173184.CrossRefGoogle Scholar
Jantzen, J. C., Representations of algebraic groups, second edition, Mathematical Surveys and Monographs, vol. 107 (American Mathematical Society, Providence, RI, 2003).Google Scholar
Kebekus, S., Families of singular rational curves, J. Algebraic Geom. 11 (2002), 245256.CrossRefGoogle Scholar
Kerr, M. and Robles, C., Classification of smooth horizontal Schubert varieties, Eur. J. Math. 3 (2017), 289310.CrossRefGoogle Scholar
Kollár, J., Rational curves on algebraic varieties, Ergebnisse der Mathematik, vol. 32 (Springer, Berlin, 1999).Google Scholar
Landsberg, J. and Manivel, L., On the projective geometry of rational homogeneous varieties, Comment. Math. Helv. 78 (2003), 65100.CrossRefGoogle Scholar
Lauritzen, N. and Thomsen, J. F., Line bundles on Bott–Samelson varieties, J. Algebraic Geom. 13 (2004), 461473.CrossRefGoogle Scholar
Mumford, D., Fogarty, J. and Kirwan, F., Geometric invariant theory, Ergebnisse der Mathematik und ihrer Grenzgebiete, vol. 34 (Springer, 1993).Google Scholar
Perrin, N., Rational curves on minuscule Schubert varieties, J. Algebra 294 (2005), 431462.CrossRefGoogle Scholar
Perrin, N., Small resolutions of minuscule Schubert varieties, Compos. Math. 143 (2007), 12551312.CrossRefGoogle Scholar
Perrin, N., Gorenstein locus of minuscule Schubert varieties, Adv. Math. 220 (2009), 505522.CrossRefGoogle Scholar
Sankaran, P. and Vanchinathan, P., Small resolutions of Schubert varieties in symplectic and orthogonal Grassmannians, Publ. Res. Inst. Math. Sci. 30 (1994), 443458.CrossRefGoogle Scholar
Sankaran, P. and Vanchinathan, P., Small resolutions of Schubert varieties and Kazhdan–Lusztig polynomials, Publ. Res. Inst. Math. Sci. 31 (1995), 465480.CrossRefGoogle Scholar
Stembridge, J. R., Minuscule elements of Weyl groups, J. Algebra 235 (2001), 722745.CrossRefGoogle Scholar
Strickland, E., Lines in $G/P$, Math. Z. 242 (2002), 227240.CrossRefGoogle Scholar
Zelevinsky, A., Small resolutions of singularities of Schubert varieties, Funct. Anal. Appl. 17 (1983), 7577.Google Scholar