Editing Boolean satisfiability problem (section)

===2-satisfiability===
{{Main|2-satisfiability}}

SAT is easier if the number of literals in a clause is limited to at most 2, in which case the problem is called '''[[2-SAT]]'''. This problem can be solved in polynomial time, and in fact is [[NL-complete|complete]] for the complexity class [[NL (complexity)|NL]]. If additionally all OR operations in literals are changed to [[Exclusive or|XOR]] operations, then the result is called '''exclusive-or 2-satisfiability''', which is a problem complete for the complexity class [[SL (complexity)|SL]] = [[L (complexity)|L]].