n System needs to be extensible with respect to inference rules, … n Should include black box algorithms with trust annotation on black box n What is trust?   Trust of inference rules, agent (might have additional granularity), source.  Look at solutions such as delegated trust in n3 n Proofs with true but not useful information- need techniques for pruning n Are there techniques like Google’s reverse links that can help? n If you want a “good explanation” that may impact the proof spec. And what is a “good explanation” n Where do ground facts ground out  (what granularity) n Provenance or other annotations on information