Extraction of k-mer coordinates from sequence ACTAGCTAGCTAG for k = 3 (panel A) and subsequent compression with a diff-transform (panel B), where the coordinates at a node's successor are expected to be the same but incremented by +1, as these nodes are likely to be consecutive in the input sequence(s). The symmetric set difference $A\mathrm{\Delta }B:=(A\cup B)\mathrm{\setminus }(A\cap B)$ is used as a diff-operation. Thus, for example, $L^{\delta }\left(\mathrm{TAG}\right)=\left(\right\{3,7,11\}\oplus 1)\mathrm{\Delta }\{4,8\}=\left\{12\right\}$. The inverse transform is performed losslessly by $L\left(v\right)=\left(L\right(v_{\mathrm{succ}}\left)\mathrm{\Delta }{L}^{\delta }\right(v\left)\right)\ominus 1$, which follows from the following property: $\left(A\mathrm{\Delta }B\right)\mathrm{\Delta }B=A\mathrm{\forall }A,B$.