In brief, when a level 3 evidence is presented by the follower and negative feedback (i.e., DRIUs) is not provided by the commander, only propositions supported by the evidence are considered to be grounded even though the DU has not yet reached state F. In general, past work on discourse has targeted dialogue consisting of only utterances, or has considered actions as subsidiary elements.
this paper targets action control dialogue, where actions are considered to be primary elements of dialogue as well as utterances.