MATHEMATICA BOHEMICA, Vol. 137, No. 4, pp. 425-447, 2012

# Monadic $\boldsymbol n\boldsymbol\times\boldsymbol m$-valued Lukasiewicz-Moisil algebras

## A. V. Figallo, C. Sanza

Aldo V. Figallo, Departamento de Matemática, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina, Instituto de Ciencias Básicas, Universidad Nacional de San Juan, 5400 San Juan, Argentina, e-mail: avfigallo@gmail.com; Claudia Sanza, Departamento de Matemática Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina

Abstract: Here we initiate an investigation into the class $\boldsymbol m\boldsymbol L\boldsymbol M_{\boldsymbol n\boldsymbol\times\boldsymbol m}$ of monadic $n\times m$-valued Lukasiewicz-Moisil algebras (or $mLM_{n \times m}$-algebras), namely $n\times m$-valued Lukasiewicz-Moisil algebras endowed with a unary operation. These algebras constitute a generalization of monadic $n$-valued Lukasiewicz-Moisil algebras. In this article, the congruences on these algebras are determined and subdirectly irreducible algebras are characterized. From this last result it is proved that $\boldsymbol m\boldsymbol L\boldsymbol M_{\boldsymbol n\boldsymbol\times\boldsymbol m}$ is a discriminator variety and as a consequence, the principal congruences are characterized. Furthermore, the number of congruences of finite $mLM_{n \times m}$-algebras is computed. In addition, a topological duality for $mLM_{n \times m}$-algebras is described and a characterization of $mLM_{n \times m}$-congruences in terms of special subsets of the associated space is shown. Moreover, the subsets which correspond to principal congruences are determined. Finally, some functional representation theorems for these algebras are given and the relationship between them is pointed out.

Keywords: $n$-valued Lukasiewicz-Moisil algebra, monadic $n$-valued Lukasiewicz-Moisil algebra, congruence, subdirectly irreducible algebra, discriminator variety, Priestley space

Classification (MSC 2010): 03G20, 06D30

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