[provenance-challenge] Optional Query 9

[Robert Clark]

Hello All,

I wanted to raise an objection I have to suggested query nine and see what kind of responses my objection yields.

Which steps were not executed because of halt? 

I believe this is *not* a provenance query, it asks a question about what may have happened in the future not a question about what has happened in the past. To me, this query seems more at home in a workflow system study rather than a challenge studying the interoperability of a provenance model.

Thank you,

Robert Clark, NCSA