Abstract
In this paper we consider fundamental properties of some types of filters (Boolean, positive implicative, implicative and fantastic filters) of BL algebras defined in Haveshki et al. (Soft Comput 10:657–664, 2006) and Turunen (Arch Math Logic 40:467–473, 2001). It is proved in Haveshki et al. (2006) that if F is a maximal and (positive) implicative filter then it is a Boolean filter. In that paper there is an open problem
Under what condition are Boolean filters positive implicative filters?
One of our results gives an answer to the problem, that is, we need no more conditions. Moreover, we give simple characterizations of those filters by an identity form ∀ x, y(t(x, y) ∈ F), where t(x, y) is a term containing x, y.
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References
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Haveshki M, Saeid AB, Eslami E (2006) Some types of filters in BL algebras. Soft Comput 10:657–664
Turunen E (1999) BL-algebras of basic fuzzy logic. Mathw soft comput 6:49-61
Turunen E (2001) Boolean deductive systems of BL-algebras. Arch Math Logic 40:467–473
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Kondo, M., Dudek, W.A. Filter theory of BL algebras. Soft Comput 12, 419–423 (2008). https://doi.org/10.1007/s00500-007-0178-7
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DOI: https://doi.org/10.1007/s00500-007-0178-7