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Nonabelian level structures, Nielsen equivalence, and Markoff triples. (English) Zbl 07782633

Summary: In this paper we establish a congruence on the degree of the map from a component of a Hurwitz space of covers of elliptic curves to the moduli stack of elliptic curves. Combinatorially, this can be expressed as a congruence on the cardinalities of Nielsen equivalence classes of generating pairs of finite groups. Building on the work of Bourgain, Gamburd, and Sarnak, we apply this congruence to show that for all but finitely many primes \(p\), the group of Markoff automorphisms acts transitively on the non-zero \(\mathbb{F}_p\)-points of the Markoff equation \(x^2+y^2+z^2-3xyz=0\). This yields a strong approximation property for the Markoff equation, the finiteness of congruence conditions satisfied by Markoff numbers, and the connectivity of a certain infinite family of Hurwitz spaces of \(\mathrm{SL}_2(\mathbb{F}_p)\)-covers of elliptic curves. With possibly finitely many exceptions, this resolves a conjecture of Bourgain, Gamburd, and Sarnak, first posed by Baragar in 1991, and a question of Frobenius, posed in 1913. Since their methods are effective, this reduces the conjecture to a finite computation.

MSC:

11D25 Cubic and quartic Diophantine equations
11J06 Markov and Lagrange spectra and generalizations
14H10 Families, moduli of curves (algebraic)
14H30 Coverings of curves, fundamental group
14D20 Algebraic moduli problems, moduli of vector bundles
14G12 Hasse principle, weak and strong approximation, Brauer-Manin obstruction
14M35 Character varieties
20D60 Arithmetic and combinatorial problems involving abstract finite groups

References:

[1] Abramovich, Dan; Corti, Alessio; Vistoli, Angelo, Twisted bundles and admissible covers, Comm. Algebra. Communications in Algebra, 31, special issue in honor of Steven L. Kleiman, 3547-3618 (2003) · Zbl 1077.14034 · doi:10.1081/AGB-120022434
[2] Abramovich, Dan; Vistoli, Angelo, Compactifying the space of stable maps, J. Amer. Math. Soc.. Journal of the Amer. Math. Soc., 15, 27-75 (2002) · Zbl 0991.14007 · doi:10.1090/S0894-0347-01-00380-0
[3] Arbarello, Enrico; Cornalba, Maurizio; Griffiths, Phillip A., Geometry of Algebraic Curves. {V}olume {II}, Grundlehren Math. Wissen., 268, xxx+963 pp. (2011) · Zbl 1235.14002 · doi:10.1007/978-3-540-69392-5
[4] Asada, Mamoru, The faithfulness of the monodromy representations associated with certain families of algebraic curves, J. Pure Appl. Algebra. Journal of Pure and Applied Algebra, 159, 123-147 (2001) · Zbl 1045.14013 · doi:10.1016/S0022-4049(00)00056-6
[5] Baragar, A., The {M}arkoff equation and equations of {H}urwitz
[6] Bass, Hyman, Covering theory for graphs of groups, J. Pure Appl. Algebra. Journal of Pure and Applied Algebra, 89, 3-47 (1993) · Zbl 0805.57001 · doi:10.1016/0022-4049(93)90085-8
[7] Bell, Renee; Booher, Jeremy; Chen, William Y.; Liu, Yuan, Tamely ramified covers of the projective line with alternating and symmetric monodromy, Algebra Number Theory. Algebra & Number Theory, 16, 393-446 (2022) · Zbl 1498.11151 · doi:10.2140/ant.2022.16.393
[8] Bertin, Jos\'{e}; M\'{e}zard, Ariane, D\'{e}formations formelles des rev\^etements sauvagement ramifi\'{e}s de courbes alg\'{e}briques, Invent. Math.. Inventiones Mathematicae, 141, 195-238 (2000) · Zbl 0993.14014 · doi:10.1007/s002220000071
[9] Bertin, Jos\'{e}; M\'{e}zard, Ariane, D\'{e}formations formelles de rev\^etements: un principe local-global, Israel J. Math.. Israel Journal of Mathematics, 155, 281-307 (2006) · Zbl 1133.14011 · doi:10.1007/BF02773957
[10] Bertin, Jos\'{e}; Romagny, Matthieu, Champs de {H}urwitz, M\'{e}m. Soc. Math. Fr. (N.S.). M\'{e}moires de la Soci\'{e}t\'{e} Math\'{e}matique de France. Nouvelle S\'{e}rie, 219 pp. (2011) · Zbl 1242.14025 · doi:10.24033/msmf.437
[11] Bertolini, Massimo; Darmon, Henri; Prasanna, Kartik, {\(p\)}-adic {\(L\)}-functions and the coniveau filtration on {C}how groups, J. Reine Angew. Math.. Journal f\"{u}r die Reine und Angewandte Mathematik. [Crelle’s Journal], 731, 21-86 (2017) · Zbl 1436.11141 · doi:10.1515/crelle-2014-0150
[12] Bombieri, Enrico, Continued fractions and the {M}arkoff tree, Expo. Math.. Expositiones Mathematicae, 25, 187-213 (2007) · Zbl 1153.11030 · doi:10.1016/j.exmath.2006.10.002
[13] Bourgain, J.; Gamburd, A.; Sarnak, P., Markoff surfaces and strong approximation: \(1 (2016)\)
[14] Bourgain, Jean; Gamburd, Alexander; Sarnak, Peter, Markoff triples and strong approximation, C. R. Math. Acad. Sci. Paris. Comptes Rendus Math\'{e}matique. Acad\'{e}mie des Sciences. Paris, 354, 131-135 (2016) · Zbl 1378.11043 · doi:10.1016/j.crma.2015.12.006
[15] Brumfiel, G. W.; Hilden, H. M., {\(SL(2)\)} Representations of Finitely Presented Groups, Contemp. Math., 187, viii+196 pp. (1995) · Zbl 0838.20006 · doi:10.1090/conm/187
[16] Bux, Kai-Uwe; Ershov, Mikhail V.; Rapinchuk, Andrei S., The congruence subgroup property for {\({\rm Aut}\,F_2\)}: a group-theoretic proof of {A}sada’s theorem, Groups Geom. Dyn.. Groups, Geometry, and Dynamics, 5, 327-353 (2011) · Zbl 1251.20035 · doi:10.4171/GGD/130
[17] Catanese, Fabrizio; L\"{o}nne, Michael; Perroni, Fabio, Genus stabilization for the components of moduli spaces of curves with symmetries, Algebr. Geom.. Algebraic Geometry, 3, 23-49 (2016) · Zbl 1354.14043 · doi:10.14231/AG-2016-002
[18] Chen, Dawei, Teichm\"{u}ller dynamics in the eyes of an algebraic geometer. Surveys on {R}ecent {D}evelopments in {A}lgebraic {G}eometry, Proc. Sympos. Pure Math., 95, 171-197 (2017) · Zbl 1393.14021
[19] Chen, William Yun, Moduli interpretations for noncongruence modular curves, Math. Ann.. Mathematische Annalen, 371, 41-126 (2018) · Zbl 1454.11110 · doi:10.1007/s00208-017-1575-6
[20] Clebsch, A., Zur {T}heorie der {R}iemann’schen {F}l\"{a}che, Math. Ann.. Mathematische Annalen, 6, 216-230 (1873) · JFM 05.0227.01 · doi:10.1007/BF01443193
[21] Arithmetic {G}eometry, xvi+353 pp. (1986) · doi:10.1007/978-1-4613-8655-1
[22] de Courcy-Ireland, Matthew; Lee, Seungjae, Experiments with the {M}arkoff surface, Exp. Math.. Experimental Mathematics, 31, 814-829 (2022) · Zbl 1523.11058 · doi:10.1080/10586458.2019.1702123
[23] De Concini, Corrado; Procesi, Claudio, The Invariant Theory of Matrices, Univ. Lecture Series, 69, v+151 pp. (2017) · Zbl 1401.15001 · doi:10.1090/ulect/069
[24] Deligne, P., Le groupe fondamental de la droite projective moins trois points. Galois Groups over {\({\bf Q}\)}, Math. Sci. Res. Inst. Publ., 16, 79-297 (1989) · Zbl 0742.14022 · doi:10.1007/978-1-4613-9649-9_3
[25] Deligne, P.; Mumford, D., The irreducibility of the space of curves of given genus, Inst. Hautes \'{E}tudes Sci. Publ. Math.. Institut des Hautes \'{E}tudes Scientifiques. Publications Math\'{e}matiques, 36, 75-109 (1969) · Zbl 0181.48803
[26] Deligne, P.; Rapoport, M., Les sch\'{e}mas de modules de courbes elliptiques. Modular Functions of One Variable, {II}, Lecture Notes in Math., 349, 143-316 (1973) · Zbl 0281.14010 · doi:10.1007/978-3-540-37855-6
[27] Demazure, Michel, R\'{e}sultant, discriminant, Enseign. Math. (2). L’Enseignement Math\'{e}matique. Revue Internationale. 2e S\'{e}rie, 58, 333-373 (2012) · Zbl 1283.13007 · doi:10.4171/LEM/58-3-5
[28] Dennin Jr., J. B., The genus of subfields of {\(K(n)\)}, Proc. Amer. Math. Soc.. Proceedings of the Amer. Math. Soc., 51, 282-288 (1975) · Zbl 0313.10022 · doi:10.2307/2040309
[29] Diamond, F.; Shurman, J., A {F}irst {C}ourse in {M}odular {F}orms, Grad. Texts in Math., 228 (2005) · Zbl 1062.11022 · doi:10.1007/978-0-387-27226-9
[30] Grothendieck, A., Chapitre {II.} \'{E}tude globale {\'e}l{\'e}mentaire de quelques classes de morphismes, Inst. Hautes. {\'E}tudes Sci. Publ. Math.. Publications Math{\'e}matiques de l�Institut des Hautes {\'E}tudes Scientifiques, 8, 5-205 (1961) · Zbl 0118.36206 · doi:10.1007/BF02699291
[31] Donkin, Stephen, The normality of closures of conjugacy classes of matrices, Invent. Math.. Inventiones Mathematicae, 101, 717-736 (1990) · Zbl 0822.20045 · doi:10.1007/BF01231523
[32] Dunfield, Nathan M.; Thurston, William P., Finite covers of random 3-manifolds, Invent. Math.. Inventiones Mathematicae, 166, 457-521 (2006) · Zbl 1111.57013 · doi:10.1007/s00222-006-0001-6
[33] Dunwoody, M. J., Nielsen transformations. Computational {P}roblems in {A}bstract {A}lgebra, 45-46 (1970) · Zbl 0191.02202
[34] Duryev, Eduard, Teichm{\"u}ller {C}urves in {G}enus {T}wo: {S}quare-tiled {S}urfaces and {M}odular {C}urves, 116 pp. (2018)
[35] Eddy, Jillian; Fuchs, Elena; Litman, Matthew; Martin, Daniel; Tripeny, Nico, Connectivity of Markoff mod-\(p\) graphs and maximal divisors (2023)
[36] Edidin, Dan; Hassett, Brendan; Kresch, Andrew; Vistoli, Angelo, Brauer groups and quotient stacks, Amer. J. Math.. American Journal of Mathematics, 123, 761-777 (2001) · Zbl 1036.14001 · doi:10.1353/ajm.2001.0024
[37] Ellenberg, Jordan S.; Venkatesh, Akshay; Westerland, Craig, Homological stability for {H}urwitz spaces and the {C}ohen-{L}enstra conjecture over function fields, Ann. of Math. (2). Annals of Mathematics. Second Series, 183, 729-786 (2016) · Zbl 1342.14055 · doi:10.4007/annals.2016.183.3.1
[38] Fried, Michael D.; V\"{o}lklein, Helmut, The inverse {G}alois problem and rational points on moduli spaces, Math. Ann.. Mathematische Annalen, 290, 771-800 (1991) · Zbl 0763.12004 · doi:10.1007/BF01459271
[39] Frobenius, G., {\"{U}}ber die {M}arkoffschen {Z}ahlen, Berl. Ber., 458-487 (1913) · JFM 44.0255.01
[40] Fulton, William, Hurwitz schemes and irreducibility of moduli of algebraic curves, Ann. of Math. (2). Annals of Mathematics. Second Series, 90, 542-575 (1969) · Zbl 0194.21901 · doi:10.2307/1970748
[41] Garion, Shelly, Connectivity of the product replacement algorithm graph of {\({\rm PSL}(2,q)\)}, J. Group Theory. Journal of Group Theory, 11, 765-777 (2008) · Zbl 1162.20047 · doi:10.1515/JGT.2008.048
[42] Garion, Shelly; Shalev, Aner, Commutator maps, measure preservation, and {\(T\)}-systems, Trans. Amer. Math. Soc.. Transactions of the Amer. Math. Soc., 361, 4631-4651 (2009) · Zbl 1182.20015 · doi:10.1090/S0002-9947-09-04575-9
[43] Goldman, William M., The modular group action on real \(SL(2)\)-characters of a one-holed torus, Geom. Topol.. Geometry and Topology, 7, 443-486 (2003) · Zbl 1037.57001 · doi:10.2140/gt.2003.7.443
[44] Goldman, William M., Trace coordinates on {F}ricke spaces of some simple hyperbolic surfaces. Handbook of {T}eichm\"{u}ller theory. {V}ol. {II}, IRMA Lect. Math. Theor. Phys., 13, 611-684 (2009) · Zbl 1175.30043 · doi:10.4171/055-1/16
[45] Grothendieck, Alexander, Sur quelques points d’alg\`ebre homologique, Tohoku Math. J. (2). The Tohoku Mathematical Journal. Second Series, 9, 119-221 (1957) · Zbl 0118.26104 · doi:10.2748/tmj/1178244839
[46] Grothendieck, Alexander; Raynaud, Mich\`{e}le, Rev\^etements {\'E}tales et {G}roupe {F}ondamental, Lecture {N}otes in {M}ath., 224, 447 pp. pp. (1971) · Zbl 0234.14002 · doi:10.1007/BFb0058656
[47] Harbater, David; Obus, Andrew; Pries, Rachel; Stevenson, Katherine, Abhyankar’s conjectures in {G}alois theory: current status and future directions, Bull. Amer. Math. Soc. (N.S.). Amer. Math. Soc.. Bulletin. New Series, 55, 239-287 (2018) · Zbl 1432.14029 · doi:10.1090/bull/1594
[48] Harbater, David; Schneps, Leila, Approximating {G}alois orbits of dessins. Geometric {G}alois {A}ctions, 1, London Math. Soc. Lecture Note Ser., 242, 205-230 (1997) · Zbl 0898.14011 · doi:10.1017/CBO9780511758874.015
[49] Hartshorne, Robin, Deformation {T}heory, Graduate Texts in Mathematics, 257, viii+234 pp. (2010) · Zbl 1186.14004 · doi:10.1007/978-1-4419-1596-2
[50] Herrlich, Frank; Schmith\"{u}sen, Gabriela, Dessins d’enfants and origami curves. Handbook of {T}eichm\"{u}ller {T}heory. {V}ol. {II}, IRMA Lect. Math. Theor. Phys., 13, 767-809 (2009) · Zbl 1203.30043 · doi:10.4171/055-1/19
[51] Hubert, Pascal; Schmidt, Thomas A., An introduction to {V}eech surfaces. Handbook of {D}ynamical {S}ystems. {V}ol. 1{B}, 501-526 (2006) · Zbl 1130.37367 · doi:10.1016/S1874-575X(06)80031-7
[52] Hurwitz, A., Ueber {R}iemann’sche {F}l\"{a}chen mit gegebenen {V}erzweigungspunkten, Math. Ann.. Mathematische Annalen, 39, 1-60 (1891) · JFM 23.0429.01 · doi:10.1007/BF01199469
[53] Jantzen, Jens Carsten, Representations of {A}lgebraic {G}roups, Math. Surveys Monogr., 107, xiv+576 pp. (2003) · Zbl 1034.20041
[54] Katz, Nicholas M.; Mazur, Barry, Arithmetic Moduli of Elliptic Curves, Ann. of Math. Stud., 108, xiv+514 pp. (1985) · Zbl 0576.14026 · doi:10.1515/9781400881710
[55] Kleiman, Steven L., Relative duality for quasicoherent sheaves, Compositio Math.. Compositio Mathematica, 41, 39-60 (1980) · Zbl 0403.14003
[56] Knudsen, Finn F., The projectivity of the moduli space of stable curves. {II}. {T}he stacks {\(M\sb{g,n} \)}, Math. Scand.. Mathematica Scandinavica, 52, 161-199 (1983) · Zbl 0544.14020 · doi:10.7146/math.scand.a-12001
[57] Knudsen, Finn Faye; Mumford, David, The projectivity of the moduli space of stable curves. {I}. {P}reliminaries on “det” and “{D}iv”, Math. Scand.. Mathematica Scandinavica, 39, 19-55 (1976) · Zbl 0343.14008 · doi:10.7146/math.scand.a-11642
[58] Knutson, Donald, Algebraic {S}paces, Lecture Notes in Math., 203, vi+261 pp. (1971) · Zbl 0221.14001 · doi:10.1007/BFb0059750
[59] Koll\'{a}r, J\'{a}nos, Quotients by finite equivalence relations. Current {D}evelopments in {A}lgebraic {G}eometry, Math. Sci. Res. Inst. Publ., 59, 227-256 (2012) · Zbl 1271.14002
[60] Kresch, Andrew; Vistoli, Angelo, On coverings of {D}eligne-{M}umford stacks and surjectivity of the {B}rauer map, Bull. London Math. Soc.. The Bulletin of the London Mathematical Society, 36, 188-192 (2004) · Zbl 1062.14004 · doi:10.1112/S0024609303002728
[61] Lang, Serge, Algebra, Graduate Texts in Math., 211, xvi+914 pp. (2002) · Zbl 0984.00001 · doi:10.1007/978-1-4613-0041-0
[62] Liu, Qing, Algebraic {G}eometry and {A}rithmetic {C}urves, Oxford Grad. Texts in Math., 6, xvi+576 pp. (2002) · Zbl 0996.14005
[63] Liu, Y. Wood, M. M.; Zureick-Brown, D., A predicted distribution for {G}alois groups of maximal unramified extensions (2019)
[64] Lochak, Pierre, On arithmetic curves in the moduli spaces of curves, J. Inst. Math. Jussieu. Journal of the Institute of Mathematics of Jussieu. JIMJ. Journal de l’Institut de Math\'{e}matiques de Jussieu, 4, 443-508 (2005) · Zbl 1094.14018 · doi:10.1017/S1474748005000101
[65] L{\"{o}}nne, Michael, Branch stabilisation for the components of {H}urwitz moduli spaces of {G}alois covers. Galois {C}overs, {G}rothendieck-{T}eichm\"{u}ller {T}heory and {D}essins d’{E}nfants, Springer Proc. Math. Stat., 330, 181-204 (2020) · Zbl 1457.14070 · doi:10.1007/978-3-030-51795-3_9
[66] Lubotzky, Alexander, Dynamics of {\({\rm Aut}(F_N)\)} actions on group presentations and representations. Geometry, {R}igidity, and {G}roup {A}ctions, Chicago Lectures in Math., 609-643 (2011) · Zbl 1266.20045
[67] Lyndon, Roger C.; Schupp, Paul E., Combinatorial {G}roup {T}heory, Classics in Math., xiv+339 pp. (2001) · Zbl 0997.20037 · doi:10.1007/978-3-642-61896-3
[68] Macbeath, A. M., Generators of the linear fractional groups. Number {T}heory, 14-32 (1969) · Zbl 0192.35703 · doi:10.1090/pspum/012/0262379
[69] Magnus, Wilhelm; Karrass, Abraham; Solitar, Donald, Combinatorial {G}roup {T}heory, xii+444 pp. (2004) · Zbl 1130.20307
[70] Manin, Yuri I., Frobenius {M}anifolds, {Q}uantum {C}ohomology, and {M}oduli {S}paces, Amer. Math. Soc. Colloq. Publ., 47, xiv+303 pp. (1999) · Zbl 0952.14032 · doi:10.1090/coll/047
[71] Markoff, A. A., Sur les formes quadratiques binaires ind\'{e}finies, Math. Ann.. Mathematische Annalen, 17, 379-399 (1880) · JFM 12.0143.02 · doi:10.1007/BF01446234
[72] Markoff, A. A., Sur les formes quadratiques binaires ind\'{e}finies, Math. Ann.. Mathematische Annalen, 15, 381-406 (1879) · JFM 11.0147.01 · doi:10.1007/BF02086269
[73] Masur, Howard; Tabachnikov, Serge, Rational billiards and flat structures. Handbook of {D}ynamical {S}ystems, {V}ol. 1A, 1015-1089 (2002) · Zbl 1057.37034 · doi:10.1016/S1874-575X(02)80015-7
[74] Matsumura, Hideyuki, Commutative {R}ing {T}heory, Cambridge Stud. Adv. Math., 8, xiv+320 pp. (1989) · Zbl 0666.13002 · doi:10.1017/CBO9781139171762
[75] McCullough, Darryl; Wanderley, Marcus, Writing elements of {\({\rm PSL}(2,q)\)} as commutators, Comm. Algebra. Communications in Algebra, 39, 1234-1241 (2011) · Zbl 1214.20046 · doi:10.1080/00927871003645383
[76] McCullough, Darryl; Wanderley, Marcus, Nielsen equivalence of generating pairs of {\({\rm SL}(2,q)\)}, Glasg. Math. J.. Glasgow Mathematical Journal, 55, 481-509 (2013) · Zbl 1284.20031 · doi:10.1017/S0017089512000675
[77] McMullen, Curtis T., Billiards and {T}eichm\"{u}ller curves on {H}ilbert modular surfaces, J. Amer. Math. Soc.. Journal of the Amer. Math. Soc., 16, 857-885 (2003) · Zbl 1030.32012 · doi:10.1090/S0894-0347-03-00432-6
[78] McMullen, Curtis T., Teichm\"{u}ller curves in genus two: discriminant and spin, Math. Ann.. Mathematische Annalen, 333, 87-130 (2005) · Zbl 1086.14024 · doi:10.1007/s00208-005-0666-y
[79] Meiri, Chen; Puder, Doron, The {M}arkoff group of transformations in prime and composite moduli, Duke Math. J.. Duke Mathematical Journal, 167, 2679-2720 (2018) · Zbl 1447.11049 · doi:10.1215/00127094-2018-0024
[80] Mumford, D.; Fogarty, J.; Kirwan, F., Geometric Invariant Theory, Ergeb. Math. Grenzgeb., 34, xiv+292 pp. (1994) · Zbl 0797.14004
[81] Nakamoto, Kazunori, Representation varieties and character varieties, Publ. Res. Inst. Math. Sci.. Kyoto Univ.. Research Institute for Mathematical Sciences. Publications, 36, 159-189 (2000) · Zbl 1070.14503 · doi:10.2977/prims/1195143100
[82] Noohi, B., Fundamental groups of algebraic stacks, J. Inst. Math. Jussieu. Journal of the Institute of Mathematics of Jussieu. JIMJ. Journal de l’Institut de Math\'{e}matiques de Jussieu, 3, 69-103 (2004) · Zbl 1052.14001 · doi:10.1017/S1474748004000039
[83] Noohi, B., Foundations of topological stacks {I} (2005)
[84] Olsson, Martin, Integral models for moduli spaces of {\(G\)}-torsors, Ann. Inst. Fourier (Grenoble). Universit\'{e} de Grenoble. Annales de l’Institut Fourier, 62, 1483-1549 (2012) · Zbl 1293.14004 · doi:10.5802/aif.2728
[85] Olsson, Martin, Algebraic Spaces and Stacks, Amer. Math. Soc. Colloq. Publ., 62, xi+298 pp. (2016) · Zbl 1346.14001 · doi:10.1090/coll/062
[86] Olsson, Martin C., ({L}og) twisted curves, Compos. Math.. Compositio Mathematica, 143, 476-494 (2007) · Zbl 1138.14017 · doi:10.1112/S0010437X06002442
[87] Osborne, R. P.; Zieschang, H., Primitives in the free group on two generators, Invent. Math.. Inventiones Mathematicae, 63, 17-24 (1981) · Zbl 0438.20017 · doi:10.1007/BF01389191
[88] Pak, Igor, What do we know about the product replacement algorithm?. Groups and Computation, {III}, Ohio State Univ. Math. Res. Inst. Publ., 8, 301-347 (2001) · Zbl 0986.68172
[89] Pikaart, M.; de Jong, A. J., Moduli of curves with non-abelian level structure. The {M}oduli {S}pace of {C}urves ({T}exel {I}sland, 1994), Progr. Math., 129, 483-509 (1995) · Zbl 0860.14024 · doi:10.1007/978-1-4612-4264-2_18
[90] Poonen, Bjorn, Rational points on varieties, Grad. Stud. in Math., 186, xv+337 pp. (2017) · Zbl 1387.14004 · doi:10.1090/gsm/186
[91] Roberts, David P.; Venkatesh, Akshay, Hurwitz monodromy and full number fields, Algebra Number Theory. Algebra & Number Theory, 9, 511-545 (2015) · Zbl 1349.14037 · doi:10.2140/ant.2015.9.511
[92] Romagny, Matthieu, Group actions on stacks and applications, Michigan Math. J.. Michigan Mathematical Journal, 53, 209-236 (2005) · Zbl 1100.14001 · doi:10.1307/mmj/1114021093
[93] Rydh, David, Existence and properties of geometric quotients, J. Algebraic Geom.. Journal of Algebraic Geometry, 22, 629-669 (2013) · Zbl 1278.14003 · doi:10.1090/S1056-3911-2013-00615-3
[94] Schmith\"{u}sen, G., An algorithm for finding the {V}eech group of an origami, Experiment. Math., 13, 459-472 (2004) · Zbl 1078.14036 · doi:10.1080/10586458.2004.10504555
[95] Schneps, Leila, The {G}rothendieck-{T}eichm\"{u}ller group {\( \widehat{\rm GT} \)}: a survey. Geometric {G}alois Actions, 1, London Math. Soc. Lecture Note Ser., 242, 183-203 (1997) · Zbl 0910.20019 · doi:10.1017/CBO9780511666124
[96] Schneps, Leila; Lochak, Pierre, Geometric {G}alois {A}ctions, 1. Geometric {G}alois {A}ctions, 1. {A}round {G}rothendieck’s {A}ctions. 1, London Math. Soc. Lecture Note Ser., 242, 5-48 (1997) · Zbl 0868.00041 · doi:10.1017/CBO9780511758874
[97] Schr\"{o}er, Stefan; Takayama, Yukihide, On equivariant formal deformation theory, Rend. Circ. Mat. Palermo (2). Rendiconti del Circolo Matematico di Palermo. Second Series, 67, 409-419 (2018) · Zbl 1409.14021 · doi:10.1007/s12215-017-0322-x
[98] Serre, Jean-Pierre, Local {F}ields, Grad. Texts in Math., 67, 241 pp. pp. (1979) · Zbl 0423.12016 · doi:10.1007/978-1-4757-5673-9
[99] translated from the {F}rench by Patrick Ion; revised by the author, Galois {C}ohomology, Springer Monogr. Math., x+210 pp. (2002) · Zbl 1004.12003
[100] Seshadri, C. S., Geometric reductivity over arbitrary base, Advances in Math.. Advances in Mathematics, 26, 225-274 (1977) · Zbl 0371.14009 · doi:10.1016/0001-8708(77)90041-X
[101] Silverman, Joseph H., The Arithmetic of Elliptic Curves, Grad. Texts in Math., 106, xx+513 pp. (2009) · Zbl 1194.11005 · doi:10.1007/978-0-387-09494-6
[102] Steinberg, Robert, Lectures on {C}hevalley {G}roups, Univ. Lecture Series, 66, xi+160 pp. (2016) · Zbl 1361.20003 · doi:10.1090/ulect/066
[103] {\relax Stacks Project Authors}, The {S}tacks {P}roject (2022)
[104] Vdovin, E. P., Maximal orders of abelian subgroups in finite simple groups, Algebra Log.. Algebra i Logika. Institut Diskretno\u{\i} Matematiki i Informatiki, 38, 131-160 (1999) · Zbl 0936.20009 · doi:10.1007/BF02671721
[105] Veech, W. A., Teichm\"{u}ller curves in moduli space, {E}isenstein series and an application to triangular billiards, Invent. Math.. Inventiones Mathematicae, 97, 553-583 (1989) · Zbl 0676.32006 · doi:10.1007/BF01388890
[106] Vistoli, Angelo, Intersection theory on algebraic stacks and on their moduli spaces, Invent. Math.. Inventiones Mathematicae, 97, 613-670 (1989) · Zbl 0694.14001 · doi:10.1007/BF01388892
[107] Weibel, Charles A., An Introduction to Homological Algebra, Cambridge Stud. Adv. Math., 38, xiv+450 pp. (1994) · Zbl 0797.18001 · doi:10.1017/CBO9781139644136
[108] Wewers, Stefan, Deformation of tame admissible covers of curves. Aspects of {G}alois Theory, London Math. Soc. Lecture Note Ser., 256, 239-282 (1999) · Zbl 0995.14008
[109] Whang, Junho Peter, Nonlinear descent on moduli of local systems, Israel J. Math.. Israel Journal of Mathematics, 240, 935-1004 (2020) · Zbl 1464.14017 · doi:10.1007/s11856-020-2085-x
[110] Zorich, Anton, Flat surfaces. Frontiers in Number Theory, Physics, and Geometry. {I}, 437-583 (2006) · Zbl 1129.32012
[111] Geometric {G}alois {A}ctions. 2. {T}he {I}nverse {G}alois {P}roblem, {M}odli {S}paces and {M}apping {C}lass, London Mathematical Society Lecture Note Series, x+347 pp. (1997) · doi:10.1017/CBO9780511666124
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