Fall 2009. NP-complete examples. Xiao Linfu. CSC3130 Tutorial 11. [email protected] Department of Computer Science & Engineering. Outline. Review of P, NP, NP-C 2 problem s Double-SAT Dominating set http://en.wikipedia.org/wiki/Dominating_set_problem. Relations. hard. NP-C.
Is there any problem even harder than NP-C?
Yes! e.g. I-go
How to show that a problem R is not easier than a problem Q?
Informally, if R can be solved efficiently, we can solve Q efficiently.
Then, if R is polynomial time solvable, then Q is polynomial time solvable.
If Q is not polynomial time solvable, then R is not polynomial time solvable.
φ’(x1, . . . , xn, y) = φ(x1, . . . , xn) ∧(y∨ y ).