  This paper introduces the de Bruijn graph edge minimization problem, which is
related to the compression of de Bruijn graphs: find the order-k de Bruijn
graph with minimum edge count among all orders. We describe an efficient
algorithm that solves this problem. Since the edge minimization problem is
connected to the BWT compression technique called "tunneling", the paper also
describes a way to minimize the length of a tunneled BWT in such a way that
useful properties for sequence analysis are preserved. Although being a
restriction, this is significant progress towards a solution to the open
problem of finding optimal disjoint blocks that minimize space, as stated in
Alanko et al. (DCC 2019).
