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Hopf Algebras and Galois Module Theory
About this Title
Lindsay N. Childs, University at Albany, Albany, NY, Cornelius Greither, Universität der Bundeswehr München, Neubiberg, Germany, Kevin P. Keating, University of Florida, Gainesville, FL, Alan Koch, Agnes Scott College, Decatur, GA, Timothy Kohl, Boston University, Boston, MA, Paul J. Truman, Keele University, Staffordshire, United Kingdom and Robert G. Underwood, Auburn University at Montgomery, Montgomery, AL
Publication: Mathematical Surveys and Monographs
Publication Year:
2021; Volume 260
ISBNs: 978-1-4704-6516-2 (print); 978-1-4704-6737-1 (online)
DOI: https://doi.org/10.1090/surv/260
Table of Contents
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Front/Back Matter
Chapters
Hopf-Galois extensions
- Hopf-Galois structures on Galois extensions of fields, regular subgroups, and skew braces
- (Non)-existence results on Hopf-Galois structures
- Hopf-Galois structures arising from fixed point free pairs of homomorphisms
- Quantitative results
- Enumeration of Hopf-Galois structures on Galois extenion of degree $mp$
- On the Galois correspondence for Hopf-Galois structures
- Normality in Hopf-Galois extensions
- Descent theory, and the structure of Hopf algebras acting on separable field extensions
- Hopf-Galois actions on purely inseparable extensions
Hopf-Galois module theory
- Hopf-Galois module theory
- Hopf orders in group rings
- Ramification theory for separable extensions of local fields
- Stable and semistable Hopf-Galois extensions
- Hopf-Galois scaffolds
- Ali A. Alabdali and Nigel P. Byott, Counting Hopf-Galois structures on cyclic field extensions of squarefree degree, J. Algebra 493 (2018), 1–19. MR 3715201, DOI 10.1016/j.jalgebra.2017.09.009
- E. Acri and M. Bonatto, Skew braces of size $pq$, Comm. Algebra 48 (2020), no. 5, 1872–1881. MR 4085764, DOI 10.1080/00927872.2019.1709480
- Ali A. Alabdali and Nigel P. Byott, Hopf-Galois structures of squarefree degree, J. Algebra 559 (2020), 58–86. MR 4093704, DOI 10.1016/j.jalgebra.2020.04.019
- A. A. Alabdali and N. P. Byott, Skew braces of squarefree order, J. Algebra Appl. (2020), 2150128.
- Shreeram Shankar Abhyankar, Local analytic geometry, Pure and Applied Mathematics, Vol. XIV, Academic Press, New York-London, 1964. MR 0175897
- E. Artin, Galois Theory - Notre Dame mathematical lectures no. 2, Field theory: Lectures delivered at the university of Notre Dame, 1942.
- J. C. Ault and J. F. Watters, Circle groups of nilpotent rings, Amer. Math. Monthly 80 (1973), 48–52. MR 316493, DOI 10.2307/2319260
- David Bachiller, Classification of braces of order $p^3$, J. Pure Appl. Algebra 219 (2015), no. 8, 3568–3603. MR 3320237, DOI 10.1016/j.jpaa.2014.12.013
- David Bachiller, Counterexample to a conjecture about braces, J. Algebra 453 (2016), 160–176. MR 3465351, DOI 10.1016/j.jalgebra.2016.01.011
- Giulia Battiston, A theory of Galois descent for finite inseparable extensions, Proc. Amer. Math. Soc. 146 (2018), no. 1, 69–83. MR 3723121, DOI 10.1090/proc/13713
- Werner Bley and Robert Boltje, Lubin-Tate formal groups and module structure over Hopf orders, J. Théor. Nombres Bordeaux 11 (1999), no. 2, 269–305 (English, with English and French summaries). MR 1745880
- Nigel P. Byott and Lindsay N. Childs, Fixed-point free pairs of homomorphisms and nonabelian Hopf-Galois structures, New York J. Math. 18 (2012), 707–731. MR 2991421
- Nigel P. Byott, Lindsay N. Childs, and G. Griffith Elder, Scaffolds and generalized integral Galois module structure, Ann. Inst. Fourier (Grenoble) 68 (2018), no. 3, 965–1010 (English, with English and French summaries). MR 3805766
- Nigel P. Byott and G. Griffith Elder, New ramification breaks and additive Galois structure, J. Théor. Nombres Bordeaux 17 (2005), no. 1, 87–107 (English, with English and French summaries). MR 2152213
- Nigel P. Byott and G. Griffith Elder, A valuation criterion for normal bases in elementary abelian extensions, Bull. Lond. Math. Soc. 39 (2007), no. 5, 705–708. MR 2365217, DOI 10.1112/blms/bdm036
- Nigel P. Byott and G. Griffith Elder, Galois scaffolds and Galois module structure in extensions of characteristic $p$ local fields of degree $p^2$, J. Number Theory 133 (2013), no. 11, 3598–3610. MR 3084290, DOI 10.1016/j.jnt.2013.04.021
- Nigel P. Byott and G. Griffith Elder, Integral Galois module structure for elementary abelian extensions with a Galois scaffold, Proc. Amer. Math. Soc. 142 (2014), no. 11, 3705–3712. MR 3251712, DOI 10.1090/S0002-9939-2014-12126-5
- Nigel P. Byott and G. Griffith Elder, Sufficient conditions for large Galois scaffolds, J. Number Theory 182 (2018), 95–130. MR 3703934, DOI 10.1016/j.jnt.2017.06.004
- Françoise Bertrandias, Sur les extensions cycliques de degré $p^{n}$ d’un corps local, Acta Arith. 34 (1979), no. 4, 361–377 (French). MR 543208, DOI 10.4064/aa-34-4-361-377
- Françoise Bertrandias and Marie-Josée Ferton, Sur l’anneau des entiers d’une extension cyclique de degré premier d’un corps local, C. R. Acad. Sci. Paris Sér. A-B 274 (1972), A1330–A1333 (French). MR 296047
- Garrett Birkhoff and Philip Hall, On the order of groups of automorphisms, Trans. Amer. Math. Soc. 39 (1936), no. 3, 496–499. MR 1501860, DOI 10.1090/S0002-9947-1936-1501860-9
- Werner Bley and Henri Johnston, Computing generators of free modules over orders in group algebras, J. Algebra 320 (2008), no. 2, 836–852. MR 2422318, DOI 10.1016/j.jalgebra.2008.01.042
- Nigel P. Byott and Günter Lettl, Relative Galois module structure of integers of abelian fields, J. Théor. Nombres Bordeaux 8 (1996), no. 1, 125–141 (English, with English and French summaries). MR 1399950
- M. V. Bondarko, Local Leopoldt’s problem for rings of integers in abelian $p$-extensions of complete discrete valuation fields, Doc. Math. 5 (2000), 657–693. MR 1808921
- M. V. Bondarko, Local Leopoldt’s problem for ideals in totally ramified $p$-extensions of complete discrete valuation fields, Algebraic number theory and algebraic geometry, Contemp. Math., vol. 300, Amer. Math. Soc., Providence, RI, 2002, pp. 27–57. MR 1936366, DOI 10.1090/conm/300/05142
- M. V. Bondarko, The Leopoldt problem for totally ramified abelian extensions of complete discrete valuation fields, Algebra i Analiz 18 (2006), no. 5, 99–129 (Russian, with Russian summary); English transl., St. Petersburg Math. J. 18 (2007), no. 5, 757–778. MR 2301042, DOI 10.1090/S1061-0022-07-00972-7
- W. Burnside, Theory of groups of finite order, Cambridge University Press, 1911.
- N. P. Byott, Galois module theory and Kummer theory for Lubin-Tate formal groups, Algebraic number theory and diophantine analysis (proceedings of conference in graz, 1998), 2000, pp. 55–67.
- Nigel P. Byott, Integral Hopf-Galois structures on degree $p^2$ extensions of $p$-adic fields, J. Algebra 248 (2002), no. 1, 334–365. MR 1879021, DOI 10.1006/jabr.2001.9053
- Nigel P. Byott, Hopf-Galois structures on field extensions with simple Galois groups, Bull. London Math. Soc. 36 (2004), no. 1, 23–29. MR 2011974, DOI 10.1112/S0024609303002595
- Nigel P. Byott, Hopf-Galois structures on Galois field extensions of degree $pq$, J. Pure Appl. Algebra 188 (2004), no. 1-3, 45–57. MR 2030805, DOI 10.1016/j.jpaa.2003.10.010
- Nigel P. Byott, Monogenic Hopf orders and associated orders of valuation rings, J. Algebra 275 (2004), no. 2, 575–599. MR 2052627, DOI 10.1016/j.jalgebra.2003.07.003
- Nigel P. Byott, Hopf-Galois structures on almost cyclic field extensions of 2-power degree, J. Algebra 318 (2007), no. 1, 351–371. MR 2363137, DOI 10.1016/j.jalgebra.2007.04.010
- Nigel P. Byott, On the integral Galois module structure of cyclic extensions of $p$-adic fields, Q. J. Math. 59 (2008), no. 2, 149–162. MR 2428073, DOI 10.1093/qmath/ham037
- Nigel P. Byott, A valuation criterion for normal basis generators of Hopf-Galois extensions in characteristic $p$, J. Théor. Nombres Bordeaux 23 (2011), no. 1, 59–70 (English, with English and French summaries). MR 2780619
- Nigel P. Byott, Nilpotent and abelian Hopf-Galois structures on field extensions, J. Algebra 381 (2013), 131–139. MR 3030514, DOI 10.1016/j.jalgebra.2013.02.008
- Nigel P. Byott, Solubility criteria for Hopf-Galois structures, New York J. Math. 21 (2015), 883–903. MR 3425626
- N. P. Byott, Cleft extensions of Hopf algebras. II, Proc. London Math. Soc. (3) 67 (1993), no. 2, 277–304. MR 1226603, DOI 10.1112/plms/s3-67.2.277
- N. P. Byott, Corrigendum: “Uniqueness of Hopf Galois structure for separable field extensions”, Comm. Algebra 24 (1996), no. 11, 3705. MR 1405283, DOI 10.1080/00927879608825779
- Nigel P. Byott, Galois structure of ideals in wildly ramified abelian $p$-extensions of a $p$-adic field, and some applications, J. Théor. Nombres Bordeaux 9 (1997), no. 1, 201–219 (English, with English and French summaries). MR 1469668
- Nigel P. Byott, Integral Galois module structure of some Lubin-Tate extensions, J. Number Theory 77 (1999), no. 2, 252–273. MR 1702149, DOI 10.1006/jnth.1999.2385
- A. Caranti, Quasi-inverse endomorphisms, J. Group Theory 16 (2013), no. 5, 779–792. MR 3101012, DOI 10.1515/jgt-2013-0012
- A. Caranti, Bi-skew braces and regular subgroups of the holomorph, 2020.
- Lindsay N. Childs and Jesse Corradino, Cayley’s theorem and Hopf Galois structures for semidirect products of cyclic groups, J. Algebra 308 (2007), no. 1, 236–251. MR 2290920, DOI 10.1016/j.jalgebra.2006.09.016
- Scott Carnahan and Lindsay Childs, Counting Hopf Galois structures on non-abelian Galois field extensions, J. Algebra 218 (1999), no. 1, 81–92. MR 1704676, DOI 10.1006/jabr.1999.7861
- E. Campedel, A. Caranti, and I. Del Corso, Hopf-Galois structures on extensions of degree $p^2q$ and skew braces of order $p^2 q$: the cyclic Sylow $p$-subgroup case, J. Algebra 556 (2020), 1165–1210. MR 4089566, DOI 10.1016/j.jalgebra.2020.04.009
- A. Caranti, F. Dalla Volta, and M. Sala, Abelian regular subgroups of the affine group and radical rings, Publ. Math. Debrecen 69 (2006), no. 3, 297–308. MR 2273982, DOI 10.5486/pmd.2006.3594
- J. W. S. Cassels and A. Fröhlich (eds.), Algebraic number theory, Academic Press, London, 1967.
- Lindsay N. Childs and Cornelius Greither, Bounds on the number of ideals in finite commutative nilpotent $\Bbb F_p$-algebras, Publ. Math. Debrecen 92 (2018), no. 3-4, 495–516. MR 3789700, DOI 10.5486/pmd.2018.8081
- Lindsay N. Childs and Susan Hurley, Tameness and local normal bases for objects of finite Hopf algebras, Trans. Amer. Math. Soc. 298 (1986), no. 2, 763–778. MR 860392, DOI 10.1090/S0002-9947-1986-0860392-3
- Stephen U. Chase, On the automorphism scheme of a purely inseparable field extension, Ring theory (Proc. Conf., Park City, Utah, 1971) Academic Press, New York, 1972, pp. 75–106. MR 0354629
- Stephen U. Chase, Infinitesimal group scheme actions on finite field extensions, Amer. J. Math. 98 (1976), no. 2, 441–480. MR 424773, DOI 10.2307/2373897
- Lindsay N. Childs, Taming wild extensions: Hopf algebras and local Galois module theory, Mathematical Surveys and Monographs, vol. 80, American Mathematical Society, Providence, RI, 2000. MR 1767499, DOI 10.1090/surv/080
- Lindsay N. Childs, On Hopf Galois structures and complete groups, New York J. Math. 9 (2003), 99–115. MR 2016184
- Lindsay N. Childs, Elementary abelian Hopf Galois structures and polynomial formal groups, J. Algebra 283 (2005), no. 1, 292–316. MR 2102084, DOI 10.1016/j.jalgebra.2004.07.009
- Lindsay N. Childs, Some Hopf Galois structures arising from elementary abelian $p$-groups, Proc. Amer. Math. Soc. 135 (2007), no. 11, 3453–3460. MR 2336557, DOI 10.1090/S0002-9939-07-08888-0
- Lindsay N. Childs, Hopf Galois structures on Kummer extensions of prime power degree, New York J. Math. 17 (2011), 51–74. MR 2781908
- Lindsay N. Childs, Fixed-point free endomorphisms and Hopf Galois structures, Proc. Amer. Math. Soc. 141 (2013), no. 4, 1255–1265. MR 3008873, DOI 10.1090/S0002-9939-2012-11418-2
- Lindsay N. Childs, On abelian Hopf Galois structures and finite commutative nilpotent rings, New York J. Math. 21 (2015), 205–229. MR 3336553
- Lindsay N. Childs, On the Galois correspondence for Hopf Galois structures, New York J. Math. 23 (2017), 1–10. MR 3611070
- Lindsay N. Childs, Skew braces and the Galois correspondence for Hopf Galois structures, J. Algebra 511 (2018), 270–291. MR 3834774, DOI 10.1016/j.jalgebra.2018.06.023
- Lindsay N. Childs, Abelian Hopf Galois structures from almost trivial commutative nilpotent algebras, New York J. Math. 25 (2019), 1421–1437. MR 4044375
- Lindsay N. Childs, Bi-skew braces and Hopf Galois structures, New York J. Math. 25 (2019), 574–588. MR 3982254
- Lindsay N. Childs, On the Galois correspondence for Hopf Galois structures arising from finite radical algebras and Zappa-Szép products, Publ. Mat. 65 (2021), no. 1, 141–163. MR 4185830, DOI 10.5565/PUBLMAT6512105
- Lindsay N. Childs, Taming wild extensions with Hopf algebras, Trans. Amer. Math. Soc. 304 (1987), no. 1, 111–140. MR 906809, DOI 10.1090/S0002-9947-1987-0906809-8
- Lindsay N. Childs, On the Hopf Galois theory for separable field extensions, Comm. Algebra 17 (1989), no. 4, 809–825. MR 990979, DOI 10.1080/00927878908823760
- Lindsay N. Childs, Hopf Galois structures on degree $p^2$ cyclic extensions of local fields, New York J. Math. 2 (1996), 86–102. MR 1420597
- S. U. Chase, D. K. Harrison, and Alex Rosenberg, Galois theory and Galois cohomology of commutative rings, Mem. Amer. Math. Soc. 52 (1965), 15–33. MR 195922
- L. E. Clarke, On Cayley’s formula for counting trees, J. London Math. Soc. 33 (1958), 471–474. MR 100854, DOI 10.1112/jlms/s1-33.4.471
- L. N. Childs and D. J. Moss, Hopf algebras and local Galois module theory, Advances in Hopf algebras, 1994, pp. 1–24.
- Charles W. Curtis and Irving Reiner, Methods of representation theory. Vol. I, Wiley Classics Library, John Wiley & Sons, Inc., New York, 1990. With applications to finite groups and orders; Reprint of the 1981 original; A Wiley-Interscience Publication. MR 1038525
- T. Crespo, A. Rio, and M. Vela, From Galois to Hopf Galois: theory and practice, Trends in number theory, Contemp. Math., vol. 649, Amer. Math. Soc., Providence, RI, 2015, pp. 29–46. MR 3415265, DOI 10.1090/conm/649/13018
- Teresa Crespo, Anna Rio, and Montserrat Vela, Non-isomorphic Hopf Galois structures with isomorphic underlying Hopf algebras, J. Algebra 422 (2015), 270–276. MR 3272077, DOI 10.1016/j.jalgebra.2014.07.038
- T. Crespo, A. Rio, and M. Vela, Induced Hopf Galois structures, J. Algebra 457 (2016), 312–322.
- Teresa Crespo, Anna Rio, and Montserrat Vela, On the Galois correspondence theorem in separable Hopf Galois theory, Publ. Mat. 60 (2016), no. 1, 221–234. MR 3447739
- T. Crespo, A. Rio, and M. Vela, Hopf Galois structures on symmetric and alternating extensions, New York J. Math. 24 (2018), 451–457.
- Lindsay N. Childs and Harold H. Smith III, Dual Hopf orders in group rings of elementary abelian $p$-groups, J. Algebra 294 (2005), no. 2, 489–518. MR 2183362, DOI 10.1016/j.jalgebra.2005.06.015
- Teresa Crespo and Marta Salguero, Hopf Galois structures on separable field extensions of odd prime power degree, J. Algebra 519 (2019), 424–439. MR 3880638, DOI 10.1016/j.jalgebra.2018.11.004
- Stephen U. Chase and Moss E. Sweedler, Hopf algebras and Galois theory, Lecture Notes in Mathematics, Vol. 97, Springer-Verlag, Berlin-New York, 1969. MR 0260724
- Lindsay N. Childs and Robert G. Underwood, Cyclic Hopf orders defined by isogenies of formal groups, Amer. J. Math. 125 (2003), no. 6, 1295–1334. MR 2018662
- Lindsay N. Childs and Robert G. Underwood, Duals of formal group Hopf orders in cyclic groups, Illinois J. Math. 48 (2004), no. 3, 923–940. MR 2114259
- Willem A. De Graaf, Classification of nilpotent associative algebras of small dimension, Internat. J. Algebra Comput. 28 (2018), no. 1, 133–161. MR 3768261, DOI 10.1142/S0218196718500078
- P. Deligne, Les corps locaux de caractéristique $p$, limites de corps locaux de caractéristique $0$, Representations of reductive groups over a local field, Travaux en Cours, Hermann, Paris, 1984, pp. 119–157 (French). MR 771673
- Leonard Eugene Dickson, Definitions of a group and a field by independent postulates, Trans. Amer. Math. Soc. 6 (1905), no. 2, 198–204. MR 1500706, DOI 10.1090/S0002-9947-1905-1500706-2
- A. J. de Jong, Finite locally free group schemes in characteristic $p$ and Dieudonné modules, Invent. Math. 114 (1993), no. 1, 89–137. MR 1235021, DOI 10.1007/BF01232664
- J. Dixon and B. Mortimer, Permutation groups, GTM, vol. 163, Springer, New York, 1996.
- Ilaria Del Corso and Lorenzo Paolo Rossi, Normal integral bases and tameness conditions for Kummer extensions, Acta Arith. 160 (2013), no. 1, 1–23. MR 3085149, DOI 10.4064/aa160-1-1
- B. de Smit, M. Florence, and L. Thomas, The valuation criterion for normal basis generators, Bull. Lond. Math. Soc. 44 (2012), no. 4, 729–737. MR 2967240, DOI 10.1112/blms/bds005
- G. Griffith Elder, Galois scaffolding in one-dimensional elementary abelian extensions, Proc. Amer. Math. Soc. 137 (2009), no. 4, 1193–1203. MR 2465640, DOI 10.1090/S0002-9939-08-09710-4
- G. Griffith Elder, A valuation criterion for normal basis generators in local fields of characteristic $p$, Arch. Math. (Basel) 94 (2010), no. 1, 43–47. MR 2581332, DOI 10.1007/s00013-009-0076-6
- G. Griffith Elder, Ramified extensions of degree $p$ and their Hopf-Galois module structure, J. Théor. Nombres Bordeaux 30 (2018), no. 1, 19–40 (English, with English and French summaries). MR 3809707
- Pavel Etingof, Travis Schedler, and Alexandre Soloviev, Set-theoretical solutions to the quantum Yang-Baxter equation, Duke Math. J. 100 (1999), no. 2, 169–209. MR 1722951, DOI 10.1215/S0012-7094-99-10007-X
- G. Griffith Elder and Robert G. Underwood, Finite group scheme extensions, and Hopf orders in $KC^2_p$ over a characteristic $p$ discrete valuation ring, New York J. Math. 23 (2017), 11–39. MR 3611071
- S. C. Featherstonhaugh, A. Caranti, and L. N. Childs, Abelian Hopf Galois structures on prime-power Galois field extensions, Trans. Amer. Math. Soc. 364 (2012), no. 7, 3675–3684. MR 2901229, DOI 10.1090/S0002-9947-2012-05503-6
- S. C. Featherstonhaugh, Hopf algebra structures on abelian Galois extensions of fields, Ph.D. Thesis, 2003.
- Marie-José Ferton, Sur l’anneau des entiers d’extensions cycliques d’un corps local, Journées Arithmétiques (Grenoble, 1973) Bull. Soc. Math. France, Mém. No. 37, Soc. Math. France, Paris, 1974, pp. 69–74 (French). MR 0374104, DOI 10.24033/msmf.130
- A. Fröhlich, Galois module structure of algebraic integers, Springer Verlag, 1983.
- A. Fröhlich and M. J. Taylor, Algebraic number theory, Cambridge Studies in Advanced Mathematics, vol. 27, Cambridge University Press, Cambridge, 1993. MR 1215934
- Genjiro Fujisaki, An elementary construction of Galois quaternion extension, Proc. Japan Acad. Ser. A Math. Sci. 66 (1990), no. 3, 80–83. MR 1051598
- I. B. Fesenko and S. V. Vostokov, Local fields and their extensions, 2nd ed., Translations of Mathematical Monographs, vol. 121, American Mathematical Society, Providence, RI, 2002. With a foreword by I. R. Shafarevich. MR 1915966, DOI 10.1090/mmono/121
- E. J. Gómez Ayala, Bases normales d’entiers dans les extensions de Kummer de degré premier, J. Théor. Nombres Bordeaux 6 (1994), no. 1, 95–116 (French, with English and French summaries). MR 1305289
- C. Greither and L. N. Childs, $p$-elementary group schemes–constructions, and Raynaud’s theory, Hopf algebras, polynomial formal groups, and raynaud orders, 1998.
- Murray Gerstenhaber, On modular field extensions, J. Algebra 10 (1968), 478–484. MR 231814, DOI 10.1016/0021-8693(68)90073-2
- Cornelius Greither and Bodo Pareigis, Hopf Galois theory for separable field extensions, J. Algebra 106 (1987), no. 1, 239–258. MR 878476, DOI 10.1016/0021-8693(87)90029-9
- D. Gil Muñoz and A. Rio, On induced Hopf Galois structures and its local Hopf Galois modules, Publ. Mat. (Barcelona) (2021), (to appear).
- C. Greither, Extensions of finite group schemes, and Hopf Galois theory over a complete discrete valuation ring, Math. Z. 210 (1992), no. 1, 37–67. MR 1161169, DOI 10.1007/BF02571782
- Benedict H. Gross, Ramification in $p$-adic Lie extensions, Journées de Géométrie Algébrique de Rennes (Rennes, 1978) Astérisque, vol. 65, Soc. Math. France, Paris, 1979, pp. 81–102. MR 563473
- Cornelius Greither, Daniel R. Replogle, Karl Rubin, and Anupam Srivastav, Swan modules and Hilbert-Speiser number fields, J. Number Theory 79 (1999), no. 1, 164–173. MR 1718724, DOI 10.1006/jnth.1999.2425
- L. Guarnieri and L. Vendramin, Skew braces and the Yang-Baxter equation, Math. Comp. 86 (2017), no. 307, 2519–2534. MR 3647970, DOI 10.1090/mcom/3161
- Marshall Hall Jr., The theory of groups, The Macmillan Company, New York, N.Y., 1959. MR 0103215
- Nickolas Heerema, A Galois theory for inseparable field extensions, Trans. Amer. Math. Soc. 154 (1971), 193–200. MR 269632, DOI 10.1090/S0002-9947-1971-0269632-4
- Volker Heiermann, De nouveaux invariants numériques pour les extensions totalement ramifiées de corps locaux, J. Number Theory 59 (1996), no. 1, 159–202 (French, with French summary). MR 1399703, DOI 10.1006/jnth.1996.0092
- Charles Helou, Non-Galois ramification theory of local fields, Algebra Berichte [Algebra Reports], vol. 64, Verlag Reinhard Fischer, Munich, 1990. MR 1076620
- Charles Helou, On the ramification breaks, Comm. Algebra 19 (1991), no. 8, 2267–2279. MR 1123123, DOI 10.1080/00927879108824258
- I. N. Herstein, Theory of rings, Math Lecture Notes, Univ. of Chicago, 1961.
- David Hilbert, Gesammelte Abhandlungen. Dritter Band. Analysis, Grundlagen der Mathematik, Physik, Verschiedenes, nebst einer Lebensgeschichte, Chelsea Publishing Co., New York, 1965 (German). MR 0188048
- Rudolf Haggenmüller and Bodo Pareigis, Hopf algebra forms of the multiplicative group and other groups, Manuscripta Math. 55 (1986), no. 2, 121–136. MR 833240, DOI 10.1007/BF01168681
- Peter John Hilton and Urs Stammbach, A course in homological algebra, Graduate Texts in Mathematics, Vol. 4, Springer-Verlag, New York-Berlin, 1971. MR 0346025
- Osamu Hyodo, Wild ramification in the imperfect residue field case, Galois representations and arithmetic algebraic geometry (Kyoto, 1985/Tokyo, 1986) Adv. Stud. Pure Math., vol. 12, North-Holland, Amsterdam, 1987, pp. 287–314. MR 948250, DOI 10.2969/aspm/01210287
- Noboru Itô, Über das Produkt von zwei abelschen Gruppen, Math. Z. 62 (1955), 400–401 (German). MR 71426, DOI 10.1007/BF01180647
- Nathan Jacobson, Abstract derivation and Lie algebras, Trans. Amer. Math. Soc. 42 (1937), no. 2, 206–224. MR 1501922, DOI 10.1090/S0002-9947-1937-1501922-7
- N. Jacobson, Galois theory of purely inseparable fields of exponent one, Amer. J. Math. 66 (1944), 645–648. MR 11079, DOI 10.2307/2371772
- Nathan Jacobson, Lie algebras, Interscience Tracts in Pure and Applied Mathematics, No. 10, Interscience Publishers (a division of John Wiley & Sons, Inc.), New York-London, 1962. MR 0143793
- Nathan Jacobson, Lectures in abstract algebra. III, Graduate Texts in Mathematics, No. 32, Springer-Verlag, New York-Heidelberg, 1975. Theory of fields and Galois theory; Second corrected printing. MR 0392906
- Henri Johnston, Explicit integral Galois module structure of weakly ramified extensions of local fields, Proc. Amer. Math. Soc. 143 (2015), no. 12, 5059–5071. MR 3411126, DOI 10.1090/proc/12634
- C. U. Jensen and N. Yui, Quaternion extensions, Algebraic geometry and commutative algebra, 1988, pp. 155–182.
- Kevin Keating, Galois scaffolds and semistable extensions, J. Number Theory 207 (2020), 110–121. MR 4017940, DOI 10.1016/j.jnt.2019.07.002
- Otto H. Kegel, Produkte nilpotenter Gruppen, Arch. Math. (Basel) 12 (1961), 90–93 (German). MR 133365, DOI 10.1007/BF01650529
- Ina Kersten, Brauergruppen von Körpern, Aspects of Mathematics, D6, Friedr. Vieweg & Sohn, Braunschweig, 1990 (German). MR 1137014
- H. F. Kreimer and N. Heerema, Modularity vs. separability for field extensions, Canadian J. Math. 27 (1975), no. 5, 1176–1182.
- Alan Koch, Timothy Kohl, Paul J. Truman, and Robert Underwood, Normality and short exact sequences of Hopf-Galois structures, Comm. Algebra 47 (2019), no. 5, 2086–2101. MR 3977722, DOI 10.1080/00927872.2018.1529237
- Alan Koch, Timothy Kohl, Paul J. Truman, and Robert Underwood, Isomorphism problems for Hopf-Galois structures on separable field extensions, J. Pure Appl. Algebra 223 (2019), no. 5, 2230–2245. MR 3906546, DOI 10.1016/j.jpaa.2018.07.014
- A. Koch, T. Kohl, P. J. Truman, and R. Underwood, The structure of Hopf algebras acting on dihedral extensions, Advances in algebra, 2019, pp. 201–218.
- Max-Albert Knus and Manuel Ojanguren, Théorie de la descente et algèbres d’Azumaya, Lecture Notes in Mathematics, Vol. 389, Springer-Verlag, Berlin-New York, 1974 (French). MR 0417149
- Alan Koch, Hopf Galois structures on primitive purely inseparable extensions, New York J. Math. 20 (2014), 779–797. MR 3262032
- Alan Koch, Primitively generated Hopf orders in characteristic $p$, Comm. Algebra 45 (2017), no. 6, 2673–2689. MR 3594547, DOI 10.1080/00927872.2016.1233235
- A. Koch, Abelian maps, bi-skew braces, and opposite pairs of Hopf-Galois structures, Proc. Amer. Math. Soc. Series B (2021), (to appear). arXiv:2007.08967.
- A. Koch, Abelian maps, brace blocks, and solutions to the Yang-Baxter equation, 2021. arXiv:2102.06104.
- Timothy Kohl, Groups of order $4p$, twisted wreath products and Hopf-Galois theory, J. Algebra 314 (2007), no. 1, 42–74. MR 2331752, DOI 10.1016/j.jalgebra.2007.04.001
- Timothy Kohl, Regular permutation groups of order $mp$ and Hopf Galois structures, Algebra Number Theory 7 (2013), no. 9, 2203–2240. MR 3152012, DOI 10.2140/ant.2013.7.2203
- Timothy Kohl, Multiple holomorphs of dihedral and quaternionic groups, Comm. Algebra 43 (2015), no. 10, 4290–4304. MR 3366576, DOI 10.1080/00927872.2014.943842
- Timothy Kohl, Hopf-Galois structures arising from groups with unique subgroup of order $p$, Algebra Number Theory 10 (2016), no. 1, 37–59. MR 3463035, DOI 10.2140/ant.2016.10.37
- Timothy Kohl, Characteristic subgroup lattices and Hopf-Galois structures, Internat. J. Algebra Comput. 29 (2019), no. 2, 391–405. MR 3934792, DOI 10.1142/S0218196719500073
- Timothy Kohl, Enumerating dihedral Hopf-Galois structures acting on dihedral extensions, J. Algebra 542 (2020), 93–115. MR 4018326, DOI 10.1016/j.jalgebra.2019.08.040
- Timothy Kohl, Classification of the Hopf Galois structures on prime power radical extensions, J. Algebra 207 (1998), no. 2, 525–546. MR 1644203, DOI 10.1006/jabr.1998.7479
- Robert L. Kruse and David T. Price, Nilpotent rings, Gordon and Breach Science Publishers, New York-London-Paris, 1969. MR 0266956
- M. Krasner, Sur la primitivité des corps $\mathfrak {P}$-adiques, Mathematica (Cluj) 13 (1937), 72–191.
- R. L. Kruse, On the circle group of a nilpotent ring, Amer. Math. Monthly 77 (1970), 168–170. MR 257130, DOI 10.2307/2317333
- Alan Koch and Paul J. Truman, Opposite skew left braces and applications, J. Algebra 546 (2020), 218–235. MR 4033084, DOI 10.1016/j.jalgebra.2019.10.033
- T. Y. Lam, Introduction to quadratic forms over fields, Springer Graduate Studies in Mathematics, vol. 67, Springer, 2005.
- Serge Lang, Algebra, Addison-Wesley Publishing Co., Inc., Reading, Mass., 1965. MR 0197234
- Richard G. Larson, Group rings over Dedekind domains, J. Algebra 5 (1967), 358–361. MR 209368, DOI 10.1016/0021-8693(67)90045-2
- Richard Gustavus Larson, Hopf algebra orders determined by group valuations, J. Algebra 38 (1976), no. 2, 414–452. MR 404413, DOI 10.1016/0021-8693(76)90232-5
- Heinrich-Wolfgang Leopoldt, Über die Hauptordnung der ganzen Elemente eines abelschen Zahlkörpers, J. Reine Angew. Math. 201 (1959), 119–149 (German). MR 108479, DOI 10.1515/crll.1959.201.119
- Cai Heng Li, The finite primitive permutation groups containing an abelian regular subgroup, Proc. London Math. Soc. (3) 87 (2003), no. 3, 725–747. MR 2005881, DOI 10.1112/S0024611503014266
- Jonathan Lubin, Elementary analytic methods in higher ramification theory, J. Number Theory 133 (2013), no. 3, 983–999. MR 2997782, DOI 10.1016/j.jnt.2012.02.017
- Jacques Martinet, Modules sur l’algèbre du groupe quaternionien, Ann. Sci. École Norm. Sup. (4) 4 (1971), 399–408 (French). MR 291208
- G. A. Miller, H. F. Blichfeldt, and L. E. Dickson, Theory and applications of finite groups, Dover Publications, Inc., New York, 1961. MR 0123600
- Yoshimasa Miyata, On Galois structure of the integers in elementary abelian extensions of local number fields, J. Number Theory 125 (2007), no. 2, 442–458. MR 2332598, DOI 10.1016/j.jnt.2006.12.005
- Y. Miyata, On the module structure of rings of integers in $\mathfrak {p}$-adic number fields over associated orders, Math. Proc. Cambridge Philos. Soc. 123 (1998), no. 2, 199–212. MR 1490195, DOI 10.1017/S0305004197002016
- M. Ram Murty and V. Kumar Murty, On groups of squarefree order, Math. Ann. 267 (1984), no. 3, 299–309. MR 738255, DOI 10.1007/BF01456092
- Susan Montgomery, Hopf algebras and their actions on rings, CBMS Regional Conference Series in Mathematics, vol. 82, Published for the Conference Board of the Mathematical Sciences, Washington, DC; by the American Mathematical Society, Providence, RI, 1993. MR 1243637, DOI 10.1090/cbms/082
- A. Mézard, M. Romagny, and D. Tossici, Models of group schemes of roots of unity, Ann. Inst. Fourier (Grenoble) 63 (2013), no. 3, 1055–1135 (English, with English and French summaries). MR 3137480, DOI 10.5802/aif.2784
- Timur Nasybullov, Connections between properties of the additive and the multiplicative groups of a two-sided skew brace, J. Algebra 540 (2019), 156–167. MR 4003478, DOI 10.1016/j.jalgebra.2019.05.005
- K. Nejabati Zenouz, On Hopf-Galois structures and skew braces of order $p^3$, Ph.D. Thesis, 2018.
- Kayvan Nejabati Zenouz, Skew braces and Hopf-Galois structures of Heisenberg type, J. Algebra 524 (2019), 187–225. MR 3905210, DOI 10.1016/j.jalgebra.2019.01.012
- Emmy Noether, Normalbasis bei Körpern ohne höhere Verzweigung, J. Reine Angew. Math. 167 (1932), 147–152 (German). MR 1581331, DOI 10.1515/crll.1932.167.147
- Jürgen Neukirch, Alexander Schmidt, and Kay Wingberg, Cohomology of number fields, 2nd ed., Grundlehren der mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 323, Springer-Verlag, Berlin, 2008. MR 2392026, DOI 10.1007/978-3-540-37889-1
- D. V. Osipov, The discrete Heisenberg group and its automorphism group, Mat. Zametki 98 (2015), no. 1, 152–155 (Russian); English transl., Math. Notes 98 (2015), no. 1-2, 185–188. MR 3399166, DOI 10.4213/mzm10694
- Bodo Pareigis, Forms of Hopf algebras and Galois theory, Topics in algebra, Part 1 (Warsaw, 1988) Banach Center Publ., vol. 26, PWN, Warsaw, 1990, pp. 75–93. MR 1171227
- Bjorn Poonen, Isomorphism types of commutative algebras of finite rank over an algebraically closed field, Computational arithmetic geometry, Contemp. Math., vol. 463, Amer. Math. Soc., Providence, RI, 2008, pp. 111–120. MR 2459993, DOI 10.1090/conm/463/09050
- Bjorn Poonen, The moduli space of commutative algebras of finite rank, J. Eur. Math. Soc. (JEMS) 10 (2008), no. 3, 817–836. MR 2421162, DOI 10.4171/JEMS/131
- Richard Rasala, Inseparable splitting theory, Trans. Amer. Math. Soc. 162 (1971), 411–448. MR 284421, DOI 10.1090/S0002-9947-1971-0284421-2
- Michel Raynaud, Schémas en groupes de type $(p,\dots , p)$, Bull. Soc. Math. France 102 (1974), 241–280 (French). MR 419467
- D. Rees, Valuations associated with a local ring. I, Proc. London Math. Soc. (3) 5 (1955), 107–128. MR 67095, DOI 10.1112/plms/s3-5.1.107
- I. Reiner, Maximal orders, London Mathematical Society Monographs, No. 5, Academic Press [Harcourt Brace Jovanovich, Publishers], London-New York, 1975. MR 0393100
- Robert Remak, Über Unterguppen direkter Produkte von drei Faktoren, J. Reine Angew. Math. 166 (1932), 65–100 (German). MR 1581299, DOI 10.1515/crll.1932.166.65
- Derek J. S. Robinson, A course in the theory of groups, Graduate Texts in Mathematics, vol. 80, Springer-Verlag, New York, 1993. MR 1261639
- Joseph J. Rotman, Advanced modern algebra. Part 2, 3rd ed., Graduate Studies in Mathematics, vol. 180, American Mathematical Society, Providence, RI, 2017. With a foreword by Bruce Reznick. MR 3677125, DOI 10.1090/gsm/180
- Wolfgang Rump, Braces, radical rings, and the quantum Yang-Baxter equation, J. Algebra 307 (2007), no. 1, 153–170. MR 2278047, DOI 10.1016/j.jalgebra.2006.03.040
- Wolfgang Rump, Classification of cyclic braces, J. Pure Appl. Algebra 209 (2007), no. 3, 671–685. MR 2298848, DOI 10.1016/j.jpaa.2006.07.001
- Wolfgang Rump, Classification of cyclic braces, II, Trans. Amer. Math. Soc. 372 (2019), no. 1, 305–328. MR 3968770, DOI 10.1090/tran/7569
- Hans-Jürgen Schneider, Cartan matrix of liftable finite group schemes, Comm. Algebra 5 (1977), no. 8, 795–819. MR 439857, DOI 10.1080/00927877708822195
- Jean-Pierre Serre, Corps locaux, Publications de l’Institut de Mathématique de l’Université de Nancago, VIII, Hermann, Paris, 1962 (French). MR 0150130
- D. A. Suprunenko and R. I. Tyškevič, Commutative matrices, Academic Press, New York, 1968.
- Agata Smoktunowicz and Leandro Vendramin, On skew braces (with an appendix by N. Byott and L. Vendramin), J. Comb. Algebra 2 (2018), no. 1, 47–86. MR 3763907, DOI 10.4171/JCA/2-1-3
- Richard G. Swan, Induced representations and projective modules, Ann. of Math. (2) 71 (1960), 552–578. MR 138688, DOI 10.2307/1969944
- Moss Eisenberg Sweedler, Structure of inseparable extensions, Ann. of Math. (2) 87 (1968), 401–410. MR 223343, DOI 10.2307/1970711
- S. Taylor, Hopf-Galois module structure of a class of tame quaternionic fields, Ph.D. Thesis, 2020.
- M. J. Taylor, On Fröhlich’s conjecture for rings of integers of tame extensions, Invent. Math. 63 (1981), no. 1, 41–79. MR 608528, DOI 10.1007/BF01389193
- Lara Thomas, A valuation criterion for normal basis generators in equal positive characteristic, J. Algebra 320 (2008), no. 10, 3811–3820. MR 2457723, DOI 10.1016/j.jalgebra.2008.05.024
- John Tate and Frans Oort, Group schemes of prime order, Ann. Sci. École Norm. Sup. (4) 3 (1970), 1–21. MR 265368
- Dajano Tossici, Models of $\mu _{p^2,K}$ over a discrete valuation ring, J. Algebra 323 (2010), no. 7, 1908–1957. With an appendix by Xavier Caruso. MR 2594655, DOI 10.1016/j.jalgebra.2010.01.012
- Cindy Tsang and Chao Qin, On the solvability of regular subgroups in the holomorph of a finite solvable group, Internat. J. Algebra Comput. 30 (2020), no. 2, 253–265. MR 4077413, DOI 10.1142/S0218196719500735
- Paul J. Truman, Towards a generalisation of Noether’s theorem to nonclassical Hopf-Galois structures, New York J. Math. 17 (2011), 799–810. MR 2862153
- Paul J. Truman, Hopf-Galois module structure of tame biquadratic extensions, J. Théor. Nombres Bordeaux 24 (2012), no. 1, 173–199 (English, with English and French summaries). MR 2914905
- Paul J. Truman, Integral Hopf-Galois structures for tame extensions, New York J. Math. 19 (2013), 647–655. MR 3119101
- Paul J. Truman, Canonical nonclassical Hopf-Galois module structure of nonabelian Galois extensions, Comm. Algebra 44 (2016), no. 3, 1119–1130. MR 3463133, DOI 10.1080/00927872.2014.999930
- Paul J. Truman, Hopf-Galois module structure of tame $C_p\times C_p$ extensions, J. Théor. Nombres Bordeaux 28 (2016), no. 2, 557–582 (English, with English and French summaries). MR 3509724
- Paul J. Truman, Commutative Hopf-Galois module structure of tame extensions, J. Algebra 503 (2018), 389–408. MR 3780002, DOI 10.1016/j.jalgebra.2018.01.047
- Paul J. Truman, Commuting Hopf-Galois structures on a separable extension, Comm. Algebra 46 (2018), no. 4, 1420–1427. MR 3780516, DOI 10.1080/00927872.2017.1346107
- Paul J. Truman, Hopf-Galois module structure of tamely ramified radical extensions of prime degree, J. Pure Appl. Algebra 224 (2020), no. 5, 106231, 13. MR 4046237, DOI 10.1016/j.jpaa.2019.106231
- Cindy Tsang, Hopf-Galois structures of isomorphic-type on a non-abelian characteristically simple extension, Proc. Amer. Math. Soc. 147 (2019), no. 12, 5093–5103. MR 4021072, DOI 10.1090/proc/14627
- Cindy Tsang, Hopf-Galois structures on a Galois $S_n$-extension, J. Algebra 531 (2019), 349–360. MR 3953015, DOI 10.1016/j.jalgebra.2019.05.006
- Cindy Tsang, Non-existence of Hopf-Galois structures and bijective crossed homomorphisms, J. Pure Appl. Algebra 223 (2019), no. 7, 2804–2821. MR 3912948, DOI 10.1016/j.jpaa.2018.09.016
- Cindy Tsang, Hopf-Galois structures on finite extensions with almost simple Galois group, J. Number Theory 214 (2020), 286–311. MR 4105712, DOI 10.1016/j.jnt.2020.04.003
- Cindy Tsang, Hopf-Galois structures on finite extensions with quasisimple Galois group, Bull. Lond. Math. Soc. 53 (2021), no. 1, 148–160. MR 4224519, DOI 10.1112/blms.12407
- Stuart Taylor and Paul J. Truman, The structure of Hopf algebras giving Hopf-Galois structures on quaternionic extensions, New York J. Math. 25 (2019), 219–237. MR 3933762
- S. Taylor and P. J. Truman, On associated orders in separable Hopf-Galois extensions, 2020.
- Robert G. Underwood and Lindsay N. Childs, Duality for Hopf orders, Trans. Amer. Math. Soc. 358 (2006), no. 3, 1117–1163. MR 2187648, DOI 10.1090/S0002-9947-05-03728-1
- Robert G. Underwood, Realizable Hopf orders in $KC_{p^3}$, J. Algebra 319 (2008), no. 11, 4426–4455. MR 2416729, DOI 10.1016/j.jalgebra.2008.02.029
- R. Underwood, An introduction to Hopf algebras, Springer, New York, 2011.
- Robert G. Underwood, Fundamentals of Hopf algebras, Universitext, Springer, Cham, 2015. MR 3379140, DOI 10.1007/978-3-319-18991-8
- R. Underwood, The structure of Hopf algebras acting on Galois extensions, 2016. talk at the Hopf Galois Theory conference Omaha.
- Robert G. Underwood, $R$-Hopf algebra orders in $KC_{p^2}$, J. Algebra 169 (1994), no. 2, 418–440. MR 1297158, DOI 10.1006/jabr.1994.1293
- Robert Underwood, The valuative condition and $R$-Hopf algebra orders in $KC_{p^3}$, Amer. J. Math. 118 (1996), no. 4, 701–743. MR 1400057
- Robert Underwood, The group of Galois extensions over orders in $KC_{p^2}$, Trans. Amer. Math. Soc. 349 (1997), no. 4, 1503–1514. MR 1407713, DOI 10.1090/S0002-9947-97-01914-4
- Leandro Vendramin, Problems on skew left braces, Adv. Group Theory Appl. 7 (2019), 15–37. MR 3974481, DOI 10.32037/agta-2019-003
- Michael Vaughan-Lee, Groups of order $p^8$ and exponent $p$, Int. J. Group Theory 4 (2015), no. 4, 25–42. MR 3416635
- William C. Waterhouse, Introduction to affine group schemes, Graduate Texts in Mathematics, vol. 66, Springer-Verlag, New York-Berlin, 1979. MR 547117
- Robert A. Wilson, The finite simple groups, Graduate Texts in Mathematics, vol. 251, Springer-Verlag London, Ltd., London, 2009. MR 2562037, DOI 10.1007/978-1-84800-988-2
- David L. Winter, The automorphism group of an extraspecial $p$-group, Rocky Mountain J. Math. 2 (1972), no. 2, 159–168. MR 297859, DOI 10.1216/RMJ-1972-2-2-159