Quantum counting

The counting paper cited from the complexity table. The abstract presents approximate counting as phase estimation on a Grover iterate, and describes it as an amplitude-estimation process. The error formula this library quotes for that estimate is the later one in Brassard, Høyer, Mosca, and Tapp (2002), on the order of the square root of a(1−a) over M plus 1/M squared. The 1998 paper is the introduction of the algorithm. This library does not yet have an algorithm page for counting.