Problems
| Is P = BPP ? |
Besides the problems in P, which are obviously in BPP, many problems were known to be in BPP but not known to be in P. The number of such problems is decreasing, and it is conjectured that P = BPP.
For a long time, one of the most famous problems that was known to be in BPP but not known to be in P was the problem of determining whether a given number is prime. However, in the 2002 paper PRIMES is in P, Manindra Agrawal and his students Neeraj Kayal and Nitin Saxena found a deterministic polynomial-time algorithm for this problem, thus showing that it is in P.
An important example of a problem in BPP (in fact in co-RP) still not known to be in P is polynomial identity testing, the problem of determining whether a polynomial is identically equal to the zero polynomial. In other words, is there an assignment of variables such that when the polynomial is evaluated the result is nonzero? It suffices to choose each variable's value uniformly at random from a finite subset of at least d values to achieve bounded error probability, where d is the total degree of the polynomial.
Read more about this topic: BPP (complexity)
Famous quotes containing the word problems:
“I respect guilt. It is a dangerous but sometimes useful beast. The guilt that made me want to solve all my children’s problems meant trouble. The guilt that made me question my role in our mother-daughter squabbles proved helpful. Yes, I care about my kids’ problems, and I long to make suggestions. But these days I wait for children to ask for help, and I give it sparingly. Some things can’t be fixed, and I tell them so.”
—Susan Ferraro (20th century)
““What we know, is a point to what we do not know.” Open any recent journal of science, and weigh the problems suggested concerning Light, Heat, Electricity, Magnetism, Physiology, Geology, and judge whether the interest of natural science is likely to be soon exhausted.”
—Ralph Waldo Emerson (1803–1882)
“Men decide far more problems by hate, love, lust, rage, sorrow, joy, hope, fear, illusion, or some other inward emotion than by reality, authority, any legal standard, judicial precedent, or statute.”
—Marcus Tullius Cicero (106–43 B.C.)