The ultimate situations - death, chance, guilt, and the uncertainty of the world - confront man with the reality of his existence.
位置测量越精确,动量测量就越不精确,反之亦然。
A mathematician's intuition is as important as rigorous proof.
A problem is in P if it can be solved quickly by a computer, and in NP if a solution can be verified quickly.
At SF Express, we believe that speed and service are the keys to winning customer trust.