A problem used as an example in ref="module.php?name=Lexikon&file=search&eid=1&query=complexity theory">complexity theory. It can be stated thus: Given a Boolean expression E, decide if there is some assignment to the variables in E such that E is true. A ref="module.php?name=Lexikon&file=search&eid=1&query=Boolean">Boolean expression is composed of Boolean variables, (logical) negation (NOT), (logical) ref="module.php?name=Lexikon&file=search&eid=1&query=conjunction">conjunction (AND) and parentheses for grouping. The satisfiability problem was the first problem to be proved to be ref="module.php?name=Lexikon&file=search&eid=1&query=NP-complete">NP-complete (by Cook). ["Introduction to Automata Theory, Languages, and Computation" by Hopcroft and Ullman, pub. Addison-Wesley]. (1994-11-11)

In addition suitable contents:
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