Consider the following alternative way of expressing conjunctive normal form. Omission of an operator indicates plus (disjunction). Multiplication (conjunction) has weaker precedence.
ac̄e * ēgm̄ * mnā = (a OR not c OR e) AND (not e OR g OR not m) AND (m OR n OR not a)
(We use letters without ascenders acegmnopqrsuvwxyz as variables so there is space for the macron indicating negation.)
Conjunctive Normal Form, which is where all the fun is for Satisfiability, is a situation in which we wish the order of operations between plus and times, between OR and AND, had been established the other way.
This was inspired by "intelligence" tests which test the order of operations (operator precedence) for arithmetic. We typically don't question why operator precedence is the way that it is, nor wonder if things could be better if precedence were different.
No comments :
Post a Comment