# How to prove membership of NP [duplicate]

My tutor often says that proving membership of NP is the easy part of proving that a problem is NP-complete, and that this should only take a minute. What I don't understand is what exactly you're suppose to do at this step   I understand that you're suppose to verify the correctness of a solution but how do I do that?

• Your question didn't make a whole lot of sense to me. I think I know what you were asking about so I edited the question to be about that. If I got it wrong, please undo the edit (click the "edited however long ago" link and then the "rollback" link for revision 1. – David Richerby Oct 19 '15 at 7:28
• Techniques to prove a problem is in NP are covered in our reference question; I recommend you take a look at that, and edit your question or post a new question if some specific aspect remains unclear. – D.W. Oct 19 '15 at 7:33