Recovery operators in quasi-Nelson logic: the prelinear case

This paper investigates recovery operators in quasi-Nelson logic, the algebraizable logical counterpart of quasi-Nelson algebras.

These form a variety of three-potent, distributive, but not necessarily involutive residuated lattices that may be regarded as a common generalization of Nelson and Heyting algebras.

We consider both consistency and determinedness operators, with a particular focus on logics and algebras that satisfy the prelinearity condition, which is well-known in the area of mathematical fuzzy logics.

We show that, essentially, all algebraic and logical results already proved for (prelinear, distributive) involutive residuated lattice-based LFIs/LFUs can be recovered in the quasi-Nelson setting, where one dispenses with the involutivity assumption.

In this setting, consistency and undeterminedness operators are no longer duals of one another, and hence call for a more fine-grained algebraic and logical formalization.