Minimizers are defined in terms of the kmer length \(k\) and the window length \(w\), and a hash function \(h\) on kmers. Robust minimizers improves over minimizers by reusing previously chosen minimizers if possible: if the minimizer of the preceding window also minimizes the hash in the current window, always choose that kmer instead of the rightmost minimizer. In this case, some specific kmer with minimal hash could be skipped because other kmers around it have the same hash.