- implication,--- equivalency (also ~-> and = are used), - negation (often written above symbol of the formula), and ~ equivalent transformation. An example of a propositional clause is m q~ = P (a) v Q (a) with constant "a". Let fil(Xl (i) .... Xnl(i)) ..... fim (Xl (i) .... ,Xnm(i)) be the atomic formulae used for writing q~i. ,x n which provide truth of every well-formed formula q~i and falsehood of W. We admit that F and W may contain common atomic formulae or their negations.
Advances in Computers, Vol. 24