Revista de la Unión Matemática Argentina
versión On-line ISSN 1669-9637
Nelson algebras arise naturally in algebraic logic as the algebraic models of Nelson's constructive logic with strong negation. This note gives two characterisations of the variety of Nelson algebras up to term equivalence, together with a characterisation of the finite Nelson algebras up to polynomial equivalence. The results answer a question of Blok and Pigozzi and clarify some earlier work of Brignole and Monteiro.
Palabras clave : Nelson algebra; residuated lattice; BCK-algebra; equationally definable principal congruences.