Abstract
A monoid K is the internal Zappa–Szép product of two submonoids, if every element of K admits a unique factorisation as the product of one element of each of the submonoids in a given order. This definition yields actions of the submonoids on each other, which we show to be structure preserving. We prove that K is a Garside monoid if and only if both of the submonoids are Garside monoids. In this case, these factors are parabolic submonoids of K and the Garside structure of K can be described in terms of the Garside structures of the factors. We give explicit isomorphisms between the lattice structures of K and the product of the lattice structures on the factors that respect the Garside normal forms. In particular, we obtain explicit natural bijections between the normal form language of K and the product of the normal form languages of its factors.
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References
Agore, A.L., Chirvăsitu, A., Ion, B., Militaru, G.: Bicrossed products for finite groups. Algebr. Represent. Theory 12(2–5), 481–488 (2009)
Agore, A.L., Militaru, G.: Extending structures II: the quantum version. J. Algebra 336, 321–341 (2011)
Brin, M.G.: On the Zappa-Szép product. Commun. Algebra 33(2), 393–424 (2005)
Brin, M.G.: The algebra of strand splitting. I. A braided version of Thompson’s group \(V\). J. Group Theory 10(6), 757–788 (2007)
Brownlowe, N., Ramagge, J., Robertson, D., Whittaker, M.F.: Zappa-Szép products of semigroups and their \(C^\ast \)-algebras. J. Funct. Anal. 266(6), 3937–3967 (2014)
Casadio, G.: Costruzione di gruppi come prodotto di sottogruppi permutabili. Univ. Roma e Ist. Naz. Alta Mat. Rend. Mat. e Appl. V 2, 348–360 (1941)
Dehornoy, P., Digne, F., Godelle, E., Krammer, D., Jean, M.: Foundations of Garside Theory. EMS Tracts in Mathematics. European Mathematical Society. http://www.math.unicaen.fr/~garside (2014)
Dehornoy, P.: Groupes de Garside. Ann. Sci. École Norm. Sup. IV 35(2), 267–306 (2002)
Dehornoy, P., Paris, L.: Gaussian groups and Garside groups, two generalisations of Artin groups. Proc. Lond. Math. Soc. III 79(3), 569–604 (1999)
Godelle, E.: Parabolic subgroups of Garside groups. J. Algebra 317(1), 1–16 (2007)
Godelle, E.: Parabolic subgroups of Garside groups II: ribbons. J. Pure Appl. Algebra 214(11), 2044–2062 (2010)
Kunze, M.: Zappa products. Acta Math. Hungar. 41(3–4), 225–239 (1983)
Picantin, M.: Petits groupes gaussiens. PhD thesis, Université de Caen (2000)
Picantin, M.: The center of thin Gaussian groups. J. Algebra 245(1), 92–122 (2001)
Rédei, L., Szép, J.: Die Verallgemeinerung der Theorie des Gruppenproduktes von Zappa–Casadio. Acta. Sci. Math. Szeged 16, 165–170 (1955)
Szép, J.: On the structure of groups which can be represented as the product of two subgroups. Acta Sci. Math. Szeged 12(Leopoldo Fejer et Frederico Riesz LXX annos natis dedicatus, Pars A), 57–61 (1950)
Szép, J.: Zur Theorie der endlichen einfachen Gruppen. Acta Sci. Math. Szeged 14, 111–112 (1951)
Szép, J.: Sulle strutture fattorizzabili. Atti Accad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Nat. VIII 32, 649–652 (1962)
Takeuchi, M.: Matched pairs of groups and bismash products of Hopf algebras. Commun. Algebra 9(8), 841–882 (1981)
Zappa, G.: Sulla costruzione dei gruppi prodotto di due dati sottogruppi permutabili tra loro. In: Atti Secondo Congresso Un. Mat. Ital., Bologna, 1940, pp. 119–125. Edizioni Cremonense, Rome (1942)
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Both authors acknowledge support under Australian Research Council’s Discovery Projects funding scheme (Project Number DP1094072). Volker Gebhardt acknowledges support under the Spanish Projects MTM2010-19355 and MTM2013-44233-P.
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Gebhardt, V., Tawn, S. Zappa–Szép products of Garside monoids. Math. Z. 282, 341–369 (2016). https://doi.org/10.1007/s00209-015-1542-4
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DOI: https://doi.org/10.1007/s00209-015-1542-4