Declerative Meaning

Declarative reading of the clause “P:-Q,R” are:
P is true if Q and R are true.
From Q and R follows P.
Procedural readings of this clause are:
To solve the problem P, first solve the subproblem Q and then R.
To satisfy P, satisfy Q and then R.


Note that ‘,’ character indicates AND operator.
Note that ‘;’ character indicates OR operator.
AND operator has a higher priority then the OR operator.
“P :- Q, R; S, T, U.” and “P :- (Q, R); (S, T, U).” clauses gives the same results.
Same clauses can be written as:
P :- Q, R.
P :- S, T, U.