Let $C$ be base coverage, $R$ is the length of reads and $K$ is the length of $k$-mer. Then $k$-mer coverage $C_k$ can be computed as $C_k = C\cdot(R - K + 1)/R$.Could someone please explain why is this equation valid (I'm mostly confused as why it is divided by $R$)?Source: Velvet manual Section 5.1
Formula for k-mer coverage
k mer
$C_k$ is defined as the number of reads containing a k-mer. The fraction of a read available to contain a k-mer is $(R-K+1)/R$, which is the number of k-mers in the read divided by its length. That times the nucleotide coverage ($C$) is then the expected coverage of the k-mer.