Wheeler Bisimulations
This work addresses the lack of efficient minimization techniques for nondeterministic Wheeler automata, which stems from the absence of a suitable equivalence relation preserving their structural properties. We introduce the novel notion of *Wheeler bisimulation*, an equivalence relation that maintains the convex structure inherent to Wheeler automata, and establish—for the first time—a unique minimal form for Wheeler NFAs. Leveraging this relation, we design a linear-time algorithm that constructs the minimal Wheeler NFA in $O(m)$ time, substantially improving upon the $O(m \log n)$ complexity of conventional bisimulation-based approaches. Our results provide both theoretical foundations and practical algorithms for the efficient processing of Wheeler languages.