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Constructing Double Magma on Groups Using Commutation Operations

Published online by Cambridge University Press:  20 November 2018

Charles C. Edmunds*
Affiliation:
Mathematics Department, Mount Saint Vincent University, Halifax, Nova Scotia, Canada, B3M 2J6 e-mail: [email protected]
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Abstract

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A magma$\left( M,\star \right)$ is a nonempty set with a binary operation. A double magma$\left( M,\star ,\bullet \right)$ is a nonempty set with two binary operations satisfying the interchange law$\left( w\star x \right)\bullet \left( y\star z \right)=\left( w\bullet y \right)\star \left( x\bullet z \right)$. We call a double magma proper if the two operations are distinct, and commutative if the operations are commutative. A double semigroup, first introduced by Kock, is a double magma for which both operations are associative. Given a non-trivial group $G$ we define a system of two magma $\left( G,\star ,\bullet \right)$ using the commutator operations $x\star y=\left[ x,y \right]\left( ={{x}^{-1}}{{y}^{-1}}xy \right)$ and $x\bullet y=\left[ y,x \right]$. We show that $\left( G,\star ,\bullet \right)$ is a double magma if and only if $G$ satisfies the commutator laws $\left[ x,y;x,z \right]=1$ and ${{\left[ w,x;y,z \right]}^{2}}=1$. We note that the first law defines the class of 3-metabelian groups. If both these laws hold in $G$, the double magma is proper if and only if there exist ${{x}_{0}},{{y}_{0}}\in G$ for which ${{\left[ {{x}_{0}},{{y}_{0}} \right]}^{2}}\ne 1$. This double magma is a double semigroup if and only if $G$ is nilpotent of class two. We construct a specific example of a proper double semigroup based on the dihedral group of order 16. In addition, we comment on a similar construction for rings using Lie commutators.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2015

References

[1] Bachmuth, S. and Lewin, J., The Jacobi identity in groups. Math. Z. 83(1964), 170176. http://dx.doi.Org/1 0.1007/BF01111 253 Google Scholar
[2] Eckmann, B. and Hilton, P. J., Group-like structures in general categories. I. Multiplications and comultiplications. Math. Ann. 145(1961/1962), 227255. http://dx.doi.Org/1 0.1007/BF01451 367 Google Scholar
[3] Kock, J., Note on commutativity of double semigroups and two-fold monodial categories. J. HomotopyRelat. Struct. 2(2007), no. 2, 217228.Google Scholar
[4] Macdonald, I. D., On certain varieties of groups. Math. Z. 76(1961), 270282. http://dx.doi.Org/1 0.1007/BF01210977 Google Scholar
[5] Neumann, B. H., On a conjecture ofHanna Neumann. Proc. Glasgow Math.Assoc. 3(1956), 1317. http://dx.doi.org/! 0.101 7/S204061 8500033384 Google Scholar