In this paper, we introduce a new algebra called ‘EQ-algebra’, which is an alternative algebra of truth values for formal fuzzy logics. It is specified by replacing implication as the main operation with a fuzzy equality. Namely, EQ-algebra is a semilattice endowed with a binary operation of fuzzy equality and a binary operation of multiplication. Implication is derived from the fuzzy equality ...

EQ-algebras introduced by Novák are algebras of truth values for a higher-order fuzzy logic (fuzzy type theory). In this paper, the compatibility of multiplication w.r.t. the fuzzy equality in an arbitrary EQ-algebra is examined. Particularly, an example indicates that the compatibility axiom does not always hold, and then a class of EQ-algebras satisfying the compatibility axiom is characteriz...

In this paper, we introduce a special algebra called EQ-algebra which has three binary operations (meet, product, fuzzy equality) and a top element. The fuzzy equality is reflexive, symmetric and transitive with respect to the product. EQ-algebra is a natural algebra proposed as an algebra of truth values on the basis of which the fuzzy type theory (a higher-order fuzzy logic) should be develop...

In [4], Urquhart gives an example of a modal logic which has the finite model property, is recursively axiomatizable but not decidable. He poses the problem of finding such a logic containing S4. We will solve this problem by constructing a logic which in addition to the required properties also defines a locally finite variety of modal algebras. (Recall that a variety is said to be locally fin...

It is shown how the schema of equivalence can be used to obtain short proofs of tautologies A, where the depth of proofs is linear in the number of variables in A. Eq (A, B, C arbitrary formulas) is the propositional pendant of the schema of identity. It can be argued that, apart form the usual propositional tautologies and inference schemas which are given as axiomatizations of propositional l...

In this paper, we introduce a notion of generalized states from an EQ-algebra E1 to another EQ-algebra E2, which is a generalization of internal states (or state operators) on an EQ-algebra E. Also we give a type of special generalized state from an EQ-algebra E1 to E1, called generalized internal states (or GI-state). Then we give some examples and basic properties of generalized (internal) st...

Poultry industry is an important production system due to providing remarkable portion of the human food and protein needs. Considering the necessity of environmental protection, the amount of environmental impacts of a turkey production unit in Iran was determined using life cycle assessment method. The required information were collected through questionnaires and interviews with farm owners....

In this paper, by using a special family of filters $mathcal{F}$ on an EQ-algebra $E$, we construct a topology $mathcal{T}_{mathcal{mathcal{F}}}$ on $E$ and show that $(E,mathcal{T}_{mathcal{F}})$ is a topological EQ-algebra. First of all, we give some properties of topological EQ-algebras and investigate the interaction of topological EQ-algebras and quotient topological EQ-algebras. Then we o...