Knowledge representation for expert systems

The objective of this work is to analyze using of the first order logic for reasoning in knowledge based systems. Merit of the predicate logic is its relative simplicity in matter of algorithm development, where it is possible to decide about validity of a sentence written in first order logic language, by using formal rules without any connection to real meanings of logical variables. In Expert systems, the first order logic is used to derivate new formulas from given axioms, where previously derived formulas are included to the axioms as well. Its process of derivation of implicit believes from explicitly given facts