This gist contains some artifacts relating to an experimental completion-like procedure for monadic one relation monoid presentations.
This procedure, if it succeeds, produces a locally confluent rewriting system with the following property: if such system is terminating, its normal forms are precisely the lexicographically minimal representatives of monoid elements under the generator ordering
Because of this, a termination proof of such rewriting system implies that the congruence class of each monoid element contains a minimum under the standard lexicographic ordering on words.