Terminology
Literal u or ?u, where u is a variable
Clause disjunction of literals
Formula, ?, conjunction of clauses
?(u) take ? and set all instances of u true; simplify
- e.g. ?=((P, ?Q)(R, Q)) then ?(Q)=P
Pure literal var appearing in a formula either as a negative literal or a positive literal (but not both)
Unit clause clause with only one literal