> Well, n^3 or n^4 might already be considered impractical in many situation and even linear time algorithms might have huge constants that make them impractica

> Well, n^3 or n^4 might already be considered impractical in many situation and even linear time algorithms might have huge constants that make them impractical. Ah, so you now you can see how pathetic our understanding of computational complexity is when we consider algorithms that are linear sometimes impractical but we cannot show we can do better than an exponentially worse off bound for SAT instances (Today's best SAT algorithms run in time 2^O(n)).