Abstract
In this paper we study endomorphism rings of finite global dimension over not necessarily normal commutative rings. These objects have recently attracted attention as noncommutative (crepant) resolutions, or NC(C)Rs, of singularities. We propose a notion of a NCCR over any commutative ring that appears weaker but generalizes all previous notions. Our results yield strong necessary and sufficient conditions for the existence of such objects in many cases of interest. We also give new examples of NCRs of curve singularities, regular local rings and normal crossing singularities. Moreover, we introduce and study the global spectrum of a ring R, that is, the set of all possible finite global dimensions of endomorphism rings of MCM R-modules. Finally, we use a variety of methods to compute global dimension for many endomorphism rings.
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References
Aleksandrov, A.G.: Nonisolated Saito singularities. Math. USSR Sbornik 65(2), 561–574 (1990)
Atiyah, M.F., Macdonald, I.G.: Introduction to commutative algebra. Addison-Wesley Publishing Co., Reading, Mass.-London-Don Mills, Ont. (1969)
Auslander, M.: On the dimension of modules and algebras. III. Global dimension. Nagoya Math. J. 9, 67–77 (1955)
Auslander, M.: Rational singularities and almost split sequences. Trans. AMS 293(2), 511–531 (1986)
Auslander, M., Platzeck, M.I., Todorov, G.: Homological theory of idempotent ideals. Trans. Amer. Math. Soc. 332(2), 667–692 (1992)
Auslander, M., Reiten, I.: Grothendieck groups of algebras with nilpotent annihilators. Proc. AMS 103(4), 1022–1024 (1988)
Bass, H.: Algebraic K-theory. W. A. Benjamin, Inc., New York-Amsterdam (1968)
Beilinson, A., Ginzburg, V., Soergel, W.: Koszul duality patterns in representation theory. J. Amer. Math. Soc 9(2), 473–527 (1996)
Böhm, J., Decker, W., Schulze, M.: Local analysis of Grauert–Remmert-type normalization algorithms. Internat. J. Algebra Comput. 24(1), 69–94 (2014)
Bourbaki, N.: Algebra II. Chapters 4–7. Elements of Mathematics (Berlin). In: Cohn, P.M., Howie, J. (eds.) Translated from the 1981 French edition. [Reprint of the 1990 English edition]. Springer, Berlin (2003)
Bridgeland, T.: Flops and derived categories. Invent. Math. 147(3), 613–632 (2002)
Bridgeland, T., King, A., Reid, M.: The MacKay correspondence as an equivalence of derived categories. J. Amer. Math. Soc. 14(3), 535–554 (2001)
Brown, K.A., Hajarnavis, C.R.: Homologically homogeneous rings. Trans. Amer. Math. Soc. 281(1), 197–208 (1984)
Bruns, W., Herzog, J.: Cohen-Macaulay rings Cambridge Studies in Advanced Mathematics, vol. 39. Cambridge University Press, Cambridge (1993)
Buchweitz, R.-O.: Desingularizing free divisors Talk at Free divisors workshop. University of Warwick (2011)
Buchweitz, R.-O., Conca, A.: New free divisors from old. J. Commut. Algebra 5(1), 17–47 (2013)
Buchweitz, R.-O., Ebeling, W., von Bothmer, H.G.: Low-dimensional singularities with free divisors as discriminants. J. Algebraic Geom. 18(2), 371–406 (2009)
Buchweitz, R.-O., Leuschke, G.J., van den Bergh, M.: Non-commutative desingularization of determinantal varieties I. Invent. Math. 182(1), 47–115 (2010)
Buchweitz, R.-O., Mond, D.: Linear free divisors and quiver representations. In: Singularities and computer algebra, vol. 324 London Math. Soc. Lecture Note Ser. pp. 41–77. Cambridge University Press, Cambridge (2006)
Buchweitz, R.-O., Pham, T. The Koszul Complex Blows up a Point (2013). In preparation
Burban, I., Iyama, O., Keller, B., Reiten, I.: Cluster tilting for one-dimensional hypersurface singularities. Adv. Math. 217(6), 2443–2484 (2008)
Curtis, C.W., Reiner, I.: Methods of representation theory. Vol. I. John Wiley & Sons, Inc., New York (1981) With applications to finite groups and orders, Pure and Applied Mathematics, A Wiley-Interscience Publication
Dao, H.: Remarks on non-commutative crepant resolutions of complete intersections. Adv. Math. 224(3), 1021–1030 (2010)
Dao, H.: What is Serre’s condition (S n ) for sheaves? (2010). URL http://mathoverflow.net/questions/22228/what-is-serres-condition-s-n-for-sheaves
Dao, H., Huneke, C.: Vanishing of Ext, cluster tilting modules and finite global dimension of endomorphism rings. Amer. J. Math. 135(2), 561–578 (2013)
Dao, H., Iyama, O., Takahashi, R., Vial, C.: Non-commutative resolutions and Grothendieck groups. To appear in J. Noncommut. Geom., arXiv:1205.4486 (2012)
de Jong, T., van Straten, D.: Deformations of the normalization of hypersurfaces. Math. Ann. 288(3), 527–547 (1990)
Doherty, B., Faber, E., Ingalls, C.: Computing global dimension of endomorphism rings via ladders . In preparation (2014)
Evans, E.G., Griffith, P.: Syzygies London Mathematical Society Lecture Note Series, vol. 106. Cambridge University Press, Cambridge (1985)
Faber, E.: Characterizing normal crossing hypersurfaces. To appear in Math. Ann., arXiv:1201.6276 (2014)
Flenner, H.: Rationale quasihomogene Singularitäten. Arch. Math. 36, 35–44 (1981)
Goodearl, K.R., Small, L.W.: Krull versus global dimension in Noetherian P.I. rings. Proc. Amer. Math. Soc. 92(2), 175–178 (1984)
Granger, M., Mond, D., Nieto Reyes, A.M.S.: Linear free divisors and the global logarithmic comparison theorem. Ann. Inst. Fourier 59(2), 811–850 (2009)
Granger, M., Mond, D., Schulze, M.: Free divisors in prehomogeneous vector spaces. Proc. Lond. Math. Soc. (3) 102(5), 923–950 (2011)
Green, E.L., Martínez-Villa, R.: Koszul and Yoneda algebras. II. In: Algebras and modules, II (Geiranger, 1996), vol. 24 CMS Conf. Proc. pp. 227–244. Amer. Math. Soc., Providence, RI (1998)
Hartshorne, R.: Algebraic Geometry Graduate Texts in Mathematics, vol. 52. Springer, New York (1977)
Hazewinkel, M., Gubareni, N., Kirichenko, V.V.: Algebras, rings and modules. Vol. 1, Mathematics and its Applications vol. 575. Kluwer Academic Publishers, Dordrecht (2004)
Huneke, C., Wiegand, R.: Tensor products of modules, rigidity and local cohomology. Math. Scand. 81(2), 161–183 (1997)
Ingalls, C., Paquette, C.: Homological dimensions for co-rank one idempotent subalgebras. arXiv:1405.5429v1 (2014)
Ingalls, C., Yasuda, T.: Log Centres of Noncommutative Crepant Resolutions are Kawamata Log Terminal: Remarks on a paper of Stafford and van den Bergh (2013). Preprint
Iyama, O.: Representation dimension and Solomon zeta function. In: Representations of finite dimensional algebras and related topics in Lie theory and geometry, Fields Inst. Commun., vol. 40, pp. 45–64. Amer. Math. Soc., Providence, RI (2004)
Iyama, O.: Auslander correspondence. Adv. Math. 210(1), 51–82 (2007)
Iyama, O., Wemyss, M.: The classification of special Cohen-Macaulay modules. Math. Z. 265(1), 41–83 (2010)
Iyama, O., Wemyss, M.: Maximal modifications and Auslander-Reiten duality for non-isolated singularities. Invent. Math. 197(3), 521–586 (2014)
Leuschke, G.J.: Endomorphism rings of finite global dimension. Canad. J. Math. 59(2), 332–342 (2007)
Leuschke, G.J.: Non-commutative crepant resolutions: scenes from categorical geometry. In: Progress in commutative algebra 1, pp. 293–361. de Gruyter, Berlin (2012)
Leuschke, G.J., Wiegand, R.: Cohen-Macaulay representations, Mathematical Surveys and Monographs, vol. 181. American Mathematical Society, Providence, RI (2012)
Looijenga, E.J.N.: Isolated singular points on complete intersections London Mathematical Society Lecture Note Series, vol. 77. Cambridge University Press, Cambridge (1984)
McConnell, J.C., Robson, J.C.: Noncommutative Noetherian rings, Graduate Studies in Mathematics, vol. 30, revised edn. American Mathematical Society, Providence, RI (2001). With the cooperation of L. W. Small
Pierce, R.S.: Associative algebras Graduate Texts in Mathematics. Studies in the History of Modern Science, 9, vol. 88. Springer, New York (1982)
Reiner, I.: Maximal orders. Academic Press [A subsidiary of Harcourt Brace Jovanovich, Publishers], London-New York (1975). London Mathematical Society Monographs, No. 5
Saito, K.: Theory of logarithmic differential forms and logarithmic vector fields. J. Fac. Sci. Univ. Tokyo 27(2), 265–291 (1980)
Saito, K.: Primitive forms for a universal unfolding of a function with an isolated critical point. J. Fac. Sci. Univ. Tokyo Sect. IA Math 28(3), 775–792 (1981)
Sekiguchi, J.: Three dimensional saito free divisors and singular curves. J. Sib. Fed. Univ. Math. Phys. 1, 33–41 (2008)
Stafford, J.T., Van den Bergh, M.: Noncommutative resolutions and rational singularities. Michigan Math. J. 57, 659–674 (2008). Special volume in honor of Melvin Hochster
Teissier, B.: The hunting of invariants in the geometry of discriminants. In: Real and complex singularities (Proc. Ninth Nordic Summer School/NAVF Sympos. Math., Oslo, 1976), pp. 565–678. Sijthoff and Noordhoff, Alphen aan den Rijn (1977)
Terao, H.: Arrangements of hyperplanes and their freeness I. J. Fac. Sci. Univ. Tokyo Sect. IA Math. 27, 293–312 (1980)
Van den Bergh, M.: Non-commutative crepant resolutions. In: The legacy of Niels Henrik Abel, pp. 749–770. Springer, Berlin (2004)
Van den Bergh, M.: Three-dimensional flops and noncommutative rings. Duke Math. J. 122(3), 423–455 (2004)
Vasconcelos, W.V.: Reflexive modules over Gorenstein rings. Proc. Amer. Math. Soc. 19, 1349–1355 (1968)
Watanabe, K.: Rational singularities with k ∗-action. In: Commutative algebra (Trento, 1981), Lecture Notes in Pure and Appl. Math., vol. 84, pp. 339–351. Dekker, New York (1983)
Yoshino, Y.: Cohen–Macaulay modules over Cohen–Macaulay rings London Mathematical Society Lecture Note Series, vol. 146. Cambridge University Press, Cambridge (1990)
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This material is based upon work supported by the National Science Foundation under Grant No. 0932078 000, while the authors were in residence at the Mathematical Science Research Institute (MSRI) in Berkeley, California, during the spring semester of 2013. H.D. was partially supported by NSF grant DMS 1104017. E.F. was supported by the Austrian Science Fund (FWF) in frame of project J3326. C.I. was supported by an NSERC Discovery grant.
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Dao, H., Faber, E. & Ingalls, C. Noncommutative (Crepant) Desingularizations and the Global Spectrum of Commutative Rings. Algebr Represent Theor 18, 633–664 (2015). https://doi.org/10.1007/s10468-014-9510-y
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DOI: https://doi.org/10.1007/s10468-014-9510-y