Abstract
Consider a finite-dimensional algebra A and any of its moduli spaces \({{\mathcal {M}}}(A,\mathbf {d})^{ss}_{\theta }\) of representations. We prove a decomposition theorem which relates any irreducible component of \({{\mathcal {M}}}(A,{\mathbf {d}})^{ss}_{\theta }\) to a product of simpler moduli spaces via a finite and birational map. Furthermore, this morphism is an isomorphism when the irreducible component is normal. As an application, we show that the irreducible components of all moduli spaces associated to tame (or even Schur-tame) algebras are rational varieties.
Similar content being viewed by others
Notes
We point out that the inclusion \(\supseteq \) in (7) does not hold if \(\sum _{x \in Q_0}\theta (x)\) is odd. Indeed, if that is the case, then one can easily find elements \(n \in G'_\theta \) such that \(n\cdot f=-f\) for any \(f \in \bigotimes _{i=1}^r S^{m_i}\left( {\text {SI}}(C_i)_{\theta } \right) \), viewed as a regular function on \(C'\).
References
Arcara, D., Bertram, A., Coskun, I., Huizenga, J.: The minimal model program for the Hilbert scheme of points on \(P^2\) and Bridgeland stability. Adv. Math. 235, 580–626 (2013) (MR 3010070)
Alim, M., Cecotti, S., Córdova, C., Espahbodi, S., Rastogi, A., Vafa, C.: \(\cal{N}=2\) quantum field theories and their BPS quivers. Adv. Theor. Math. Phys. 18(1), 27–127 (2014) (MR 3268234 )
Álvarez-Cónsul, L., King,Alastair.: A functorial construction of moduli of sheaves. Invent. Math. 168(3), 613–666 (2007) (MR 2299563)
Altmann, K., Hille, L.:Strong exceptional sequences provided by quivers. Algebr. Represent. Theory 2(1), 1–17 (2000h:16019) (1999) (MR 1688469)
Assem, I., Simson, D., Skowroński, A.: Elements of the representation theory of associative algebras. Vol. 1: Techniques of representation theory, London Mathematical Society Student Texts, vol. 65. Cambridge University Press, Cambridge (2006j:16020) (2006) (MR 2197389 )
Bleher, F.M., Chinburg, T., Zimmermann, Huisgen, B.:The geometry of finite dimensional algebras with vanishing radical square. J. Algebra 425, 146–178 (2015) (MR 3295982)
Bodnarchuk, L., Drozd, Y.: One class of wild but brick-tame matrix problems. J. Algebra 323(10), 3004–3019 (2011c:16045) (2010) (MR 2609188)
Bobiński, G.: On the zero set of semi-invariants for regular modules over tame canonical algebras. J. Pure Appl. Algebra 212(6), 1457–1471 (2008) (MR 2391660)
Bobiński, G.: On moduli spaces for quasitilted algebras. Algebra Number Theory 8(6), 1521–1538 (2014) (MR 3267143)
Bobiński, G.: Semi-invariants for concealed-canonical algebras. J. Pure Appl. Algebra 219(1), 59–76(2015) (MR 3240823)
Bondal, A.I. : Representations of associative algebras and coherent sheaves. Izv. Akad. Nauk SSSR Ser. Mat. 53(1), 25–44 (1989) (MR 992977)
Bondal, A.I. : Helices, representations of quivers and Koszul algebras, Helices and vector bundles. Lond. Math. Soc. Lecture Note Ser., vol. 148. Cambridge Univ. Press, Cambridge, pp. 75–95 (1990) (MR 1074784)
Bongartz, K.:Some geometric aspects of representation theory, Algebras and modules, I (Trondheim, 1996), CMS Conf. Proc., vol. 23, pp. 1–27. Am. Math. Soc., Providence, RI (99j:16005) (1998) (MR1648601)
Bridgeland, T.: Scattering Diagrams, Hall Algebras and Stability Conditions. arXiv:1603.00416 (2016)
Bobiński, G., Skowroński, A.:Geometry of modules over tame quasi-tilted algebras. Colloq. Math. 79(1), 85–118 (2000i:14067) (1999) (MR1671811 )
Crawley-Boevey, W.: Tameness of biserial algebras. Arch. Math. (Basel) 65(5), 399–407 (1995) (MR1354686)
Crawley-Boevey, W.: Decomposition of Marsden-Weinstein reductions for representations of quivers. Compos. Math. 130(2), 225–239 (2002) (MR1883820)
Crawley-Boevey, W.: Normality of Marsden-Weinstein reductions for representations of quivers. Math. Ann. 325(1), 55–79 (2003) (MR 1957264)
Crawley-Boevey, W., Schröer, J.: Irreducible components of varieties of modules. J. Reine Angew. Math. 553, 201–220 (2004a:16020) (2002) (MR 1944812)
Carroll, A.T., Chindris, C.: Moduli spaces of modules of Schur-tame algebras. Algebr. Represent. Theory 18(4), 961–976 (2015) (MR 3372127)
Carroll, A.T., Chindris, C., Kinser, R., Weyman, J.: Moduli spaces of representations of special biserial algebras. Int. Math. Res. Not. (2018). https://doi.org/10.1093/imrn/rny028
Chindris, C.: Orbit semigroups and the representation type of quivers. J. Pure Appl. Algebra 213(7), 1418–1429 (2010a:16024) (2009) (MR2497586)
Chindris, C.: Cluster fans, stability conditions, and domains of semi-invariants. Trans. Am. Math. Soc. 363(4), 2171–2190 (2011m:16024) (2011) (MR 2746679)
Chindris, C.: Geometric characterizations of the representation type of hereditary algebras and of canonical algebras. Adv. Math. 228(3), 1405–1434 (2012h:16033) (2011) (MR 2824559)
Chindris, C.: On the invariant theory for tame tilted algebras. Algebra Number Theory 7(1), 193–214 (2013) (MR 3037894)
Chindris, C., Kline, D.: On locally semi-simple representations of quivers. J. Algebra 467, 284–306 (2016) (MR 3545962)
Chindris, C., Kinser, R., Weyman, J.: Module varieties and representation type of finite-dimensional algebras. Int. Math. Res. Not. IMRN (3), 631–650 (2015) (MR 3340331)
Craw, A., Smith, G.G.: Projective toric varieties as fine moduli spaces of quiver representations. Am. J. Math. 130(6), 1509–1534 (2010b:14101) (2008) (MR 2464026)
Córdova, C., Shu Heng, S.: An index formula for supersymmetric quantum mechanics. J. Singul. 15 14–35 (2016) (MR 3562853)
Carroll, A.T., Weyman, J.: Semi-invariants for gentle algebras, Noncommutative birational geometry, representations and combinatorics. Contemp. Math., vol. 592, pp. 111–136. Am. Math. Soc., Providence, RI (2013) (MR 3087942)
Derksen, H., Kemper, G.: Computational Invariant Theory, Invariant Theory and Algebraic Transformation Groups, I, Springer-Verlag, Berlin, Encyclopaedia of Mathematical Sciences, vol. 130 (2003g:13004) (2002) (MR 1918599)
de la Peña, J.A.: On the dimension of the module-varieties of tame and wild algebras. Commun. Algebra 19(6), 1795–1807 (92i:16016) (1991) (MR 1113958)
Domokos, M.: On singularities of quiver moduli. Glasg. Math. J. 53(1), 131–139 (2012a:16029) (2011) (MR 2747139)
Derksen, H., Weyman, J.: Semi-invariants of quivers and saturation for Littlewood-Richardson coefficients. J. Am. Math. Soc. 13(3), 467–479 (2000) (MR 1758750)
Derksen, H.: The combinatorics of quiver representations. Ann. Inst. Fourier (Grenoble) 61(3), 1061–1131 (2011) (MR 2918725)
Faltings, G.:Algebraic loop groups and moduli spaces of bundles. J. Eur. Math. Soc. (JEMS) 5(1), 41–68 (2003) (MR 1961134)
Geiss, C.: On degenerations of tame and wild algebras. Arch. Math. (Basel) 64(1), 11–16 (95k:16014) (1995) (MR 1305654)
Geiss, Ch., Schröer, J.: Varieties of modules over tubular algebras. Colloq. Math. 95(2), 163–183 (2004d:16026) (2003) (MR 1967418)
Hartshorne, R.: Algebraic Geometry. Springer-Verlag, New York, Graduate Texts in Mathematics, No. 52 (1977) (MR 0463157)
Hille, L.: Tilting line bundles and moduli of thin sincere representations of quivers. An. Ştiinţ. Univ. Ovidius Constanţa Ser. Mat. vol. 4(2), pp. 76–82. Representation theory of groups, algebras, and orders (Constanţa, 1995) (97h:16017) (1996) (MR 1428456)
Hille, L.: Toric quiver varieties, Algebras and modules, II (Geiranger, 1996), CMS Conf. Proc., vol. 24, Amer. Math. Soc., Providence, RI, pp. 311–325 (99h:14012) (1998) (MR 1648634)
Zimmermann, B.H.: The geometry of uniserial representations of finite-dimensional algebra. I. J. Pure Appl. Algebra 127(1), 39–72 (1998) (MR 1609508)
Zimmermann, B.H..: Fine and coarse moduli spaces in the representation theory of finite dimensional algebras, expository lectures on representation theor. Contemp. Math., vol. 607, pp. 1–34. Am. Math. Soc., Providence, RI (2014) (MR 3204864)
Igusa, K., Orr, K., Todorov, G., Weyman, J.: Cluster complexes via semi-invariants. Compos. Math. 145(4), 1001–1034 (2009) (MR 2521252)
Joyce, D., Song, Y.: A theory of generalized Donaldson-Thomas invariants. Mem. Am. Math. Soc. 217(1020), iv+199 (2012) (MR 2951762)
King, A.D.: Moduli of representations of finite-dimensional algebras. Q. J. Math. Oxford Ser. (2) 45(180), 515–530 (1994)
Kontsevich, M., Soibelman, Y.: Cohomological Hall algebra, exponential Hodge structures and motivic Donaldson-Thomas invariant. Commun. Numb. Theory Phys. 5(2), 231–352 (2011) (MR 2851153)
Lusztig, G.: Canonical bases arising from quantized enveloping algebras. J. Am. Math. Soc. 3(2), 447–498 (90m:17023) (1990) (MR 1035415)
Mozgovoy, S.: On the motivic Donaldson-Thomas invariants of quivers with potential. Math. Res. Lett. 20(1), 107–118 (2013) (MR 3126726)
Nakajima, H.: Varieties associated with quivers, Representation theory of algebras and related topics (Mexico City, 1994), CMS Conf. Proc., vol. 19, pp. 139–157. Am. Math. Soc., Providence, RI (1996) (MR 1388562)
Prest, Mi.: Model Theory and Modules, London Mathematical Society Lecture Note Series, vol. 130. Cambridge University Press, Cambridge (1988) (MR 933092)
Reineke, M.: The Harder-Narasimhan system in quantum groups and cohomology of quiver moduli. Invent. Math. 152(2), 349–368 (2003) (MR 1974891)
Reineke, M.: Framed quiver moduli, cohomology, and quantum groups. J. Algebra 320(1), 94–115 (2008) (MR 2417980)
Reineke, M.: Cohomology of quiver moduli, functional equations, and integrality of Donaldson-Thomas type invariants. Compos. Math. 147(3), 943–964 (2011) (MR 2801406 )
Riedtmann, Ch.: Tame quivers, semi-invariants, and complete intersections. J. Algebra 279(1), 362–382 (2005j:16015) (2004) (MR 2078406)
Ringel, C.M.: The rational invariants of the tame quivers. Invent. Math. 58(3), 217–239 (81f:16048) (1980) (MR 571574)
Ringel, C.M.: On algorithms for solving vector space problems. II. Tame algebras, Representation theory, I (Proc. Workshop, Carleton Univ., Ottawa, Ont., 1979), Lecture Notes in Math., vol. 831, pp. 137–287. Springer, Berlin (1980) (MR 607143)
Ringel, C.: Tame algebras and integral quadratic forms. Lecture Notes in Mathematics, vol. 1099. Springer, Berlin (1984) (MR 0774589)
Riedtmann, Ch., Zwara, G.: On the zero set of semi-invariants for tame quivers. Comment. Math. Helv. 79(2), 350–361 (2005g:16024) (2004) (MR 2059437)
Riedtmann, Ch., Zwara, G.: The zero set of semi-invariants for extended Dynkin quivers. Trans. Am. Math. Soc. 360(12), 6251–6267 (2009i:14064) (2008) (MR2434286)
Schofield, A.: Birational classification of moduli spaces of representations of quivers. Indag. Math. (N.S.) 12(3), 407–432 (2001) (MR 1914089
Schiffler, R.: Quiver representations, CMS Books in Mathematics/Ouvrages de Mathématiques de la SMC, Springer, Cham (2014) (MR 3308668)
Schofield, A., van den Bergh, M.: Semi-invariants of quivers for arbitrary dimension vectors. Indag. Math. (N.S.) 12(1), 125–138 (2001) (MR 1908144)
Skowroński, A., Weyman, J.: The algebras of semi-invariants of quivers. Transform. Groups 5(4), 361–402 (2001m:16017) (2000) (MR 1800533)
Zwara, G.: Singularities of orbit closures in module varieties, Representations of algebras and related topics, pp. 661–725. EMS Ser. Congr. Rep., Eur. Math. Soc., Zürich (2011) (MR 2931906)
Acknowledgements
We wish to thank Grzegorz Bobiński and Alastair King for discussions that led to improvements of our paper. We are especially thankful to Harm Derksen for clarifying discussions on some of the results in [35]. The first author (C.C.) was supported by the NSA under grant H98230-15-1-0022.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Chindris, C., Kinser, R. Decomposing moduli of representations of finite-dimensional algebras. Math. Ann. 372, 555–580 (2018). https://doi.org/10.1007/s00208-018-1687-7
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00208-018-1687-7