A fully polynomial-time randomized approximation scheme, abbreviated FPRAS, is a randomized algorithm that, given an input
and
, returns an estimate
of a nonnegative quantity
satisfying
in time bounded by a polynomial in the input length and . Independent repetitions can increase the success
probability (Jerrum et al. 1986, §6).
Chen and Liu (2026) gave such a scheme for counting common matroid bases of two matroids on a common ground set, given by independence oracles. An independence oracle decides whether a specified subset is independent. They also gave an algorithm running in polynomial time for approximately uniform sampling of common matroid bases when at least one common matroid basis exists. Chen and Liu (2026) report extensive AI assistance in developing their proof ideas.