P denotes set of problems which can be solved in polynomial time i.e. having solution times proportional to O(n raise to k), k is any constant. Whereas, NP is class of problems whose solution can be verified in polynomial time and its solution times for some inputs might go near exponential times or so...
The question “Does NP equal P?” means “If the solution to a problem can be verified in polynomial time, can it be found in polynomial time?”
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