Essential Variables and Separable Sets in Universal Algebra

Multiple Valued Logic, An International Journal, 2002, Vol. 8(2), pp. 165-181 The study of essential and strongly essential variables in functions defined on finite sets is a part of $k$-valued logic. We extend the main definitions from functions to terms. This allows us to apply concepts and results of Universal Algebra. On the basis of the concept of a separable set of variables in a term we introduce a new notion of complexity of terms, algebras and varieties and give examples.