some np problem

SAT  boolean satisfication , first np complete problem

Set cover

in G=(V,E)

minimum vertex cover, a special case of set cover

maximum clique,

maximum indepedent set

 

what is the defnination of NP? NPC? NP-hard? whtat is the meaning of NP!=P or NP=P?

How to prove a problem is NPC?

oracle machine? or Turing machine? Deterministic Turing Machine? Non-Denterministic Turing Machine?