Abstract:
It is shown that each algebraic action of a simply connected reductive algebraic group G on an affine algebraic variety X can be contracted (in a flat one-dimensional family of actions) to a canonical action of G on a certain affine variety grX having some very special properties. It is shown that X and grX have many algebro-geometric properties in common. As an application, we prove the Procesi–Kraft conjecture to the effect that the singularities of the closures of orbits in the case of spherical stabilizer are rational. It is assumed that the ground field has characteristic zero.
Bibliography: 37 titles.
Andrew Dancer, Julius F. Grimminger, Johan Martens, Zhenghao Zhong, “Complex symplectic contractions and 3d mirrors”, J. High Energ. Phys., 2024:11 (2024)
Ya. Li, Ch. Li, “O predelakh potoka Kelera—Richchi na gruppovykh kompaktifikatsiyakh Fano”, Materialy Mezhdunarodnoi konferentsii «Klassicheskaya i sovremennaya geometriya», posvyaschennoi 100-letiyu so dnya rozhdeniya professora Levona Sergeevicha Atanasyana (15 iyulya 1921 g.—5 iyulya 1998 g.). Moskva, 1–4 noyabrya 2021 g. Chast 3, Itogi nauki i tekhn. Sovrem. mat. i ee pril. Temat. obz., 222, VINITI RAN, M., 2023, 30–41
Dmitri I. Panyushev, “The Frobenius semiradical, generic stabilizers, and Poisson center for nilradicals”, Can. J. Math.-J. Can. Math., 2023, 1
Christopher Manon, Jihyeon Jessie Yang, “Tropical geometry and Newton–Okounkov cones for Grassmannian of planes from compactifications”, Can. J. Math.-J. Can. Math., 74:1 (2022), 199
David Ben-Zvi, Iordan Ganev, “Wonderful asymptotics of matrix coefficient D-modules”, Advances in Mathematics, 408 (2022), 108578
Adrien Dubouloz, Isac Hedén, Takashi Kishimoto, “Rees algebras of additive group actions”, Math. Z., 301:1 (2022), 593
Yiannis Sakellaridis, Jonathan Wang, “Intersection complexes and unramified 𝐿-factors”, J. Amer. Math. Soc., 35:3 (2021), 799
Kiumars Kaveh, Christopher Manon, “Khovanskii Bases, Higher Rank Valuations, and Tropical Geometry”, SIAM J. Appl. Algebra Geometry, 3:2 (2019), 292
E. B. Vinberg, S. G. Gindikin, “Degeneration of Horospheres in Spherical Homogeneous Spaces”, Funct. Anal. Appl., 52:2 (2018), 83–92
Kiumars Kaveh, Christopher Manon, “Spherical Tropical Geometry: a Survey of Recent Developments”, Acta. Math. Sin.-English Ser., 34:3 (2018), 454
Gergely Bérczi, “On the Popov–Pommerening conjecture for linear algebraic groups”, Compositio Math., 154:1 (2018), 36
Roman Avdeev, Stéphanie Cupit-Foutou, “New and old results on spherical varieties via moduli theory”, Advances in Mathematics, 328 (2018), 1299
Roger Howe, Sangjib Kim, Soo Teck Lee, Progress in Mathematics, 323, Representation Theory, Number Theory, and Invariant Theory, 2017, 265
Gene Freudenburg, Encyclopaedia of Mathematical Sciences, 136.3, Algebraic Theory of Locally Nilpotent Derivations, 2017, 167
Xin Fang, Ghislain Fourier, Peter Littelmann, “Essential bases and toric degenerations arising from birational sequences”, Advances in Mathematics, 312 (2017), 107
P. Bravi, R. Chirivì, J. Gandini, A. Maffei, “Standard Monomial Theory for Wonderful Varieties”, Algebr Represent Theor, 19:2 (2016), 489
Joachim Hilgert, Christopher Manon, Johan Martens, “Contraction of Hamiltonian K-Spaces”, Int Math Res Notices, 2016, rnw191
A. A. Gornitskii, “Essential Signatures and Canonical Bases of Irreducible Representations of the Group G2”, Math. Notes, 97:1 (2015), 30–41
V. S. Zhgun, “Malaya gruppa Veilya i mnogoobrazie vyrozhdennykh orisfer”, Chebyshevskii sb., 16:4 (2015), 164–187