Editing Complexity class (section)

====Completeness====
If a problem <math>X</math> is hard for '''C''' and is also in '''C''', then <math>X</math> is said to be '''[[complete (complexity)|complete]]''' for '''C'''. This means that <math>X</math> is the hardest problem in '''C''' (since there could be many problems that are equally hard, more precisely <math>X</math> is as hard as the hardest problems in '''C'''). 

Of particular importance is the class of [[NP-complete|'''NP'''-complete]] problems—the most difficult problems in '''NP'''. Because all problems in '''NP''' can be polynomial-time reduced to '''NP'''-complete problems, finding an '''NP'''-complete problem that can be solved in polynomial time would mean that '''P'''&nbsp;=&nbsp;'''NP'''.