Is a derivation proceeding conducted ex parte?

A derivation proceeding is indeed conducted ex parte, meaning that it generally involves only one party presenting evidence to the United States Patent and Trademark Office (USPTO) without the other party being present. This type of proceeding is initiated when a patent applicant believes that their work has been derived from their own invention through another's claims in a patent application.

In such cases, the focus is on determining whether the second applicant’s claims are substantively derived from the first applicant's work, and the process is primarily managed by the USPTO, where the party alleging derivation presents its case.

The other choices mention scenarios that imply participation from both parties, which does not align with the nature of ex parte proceedings. In this context, the emphasis is on the unilateral presentation of evidence, underscoring that derivation proceedings are strictly between the applicant asserting the derivation and the patent office itself. Therefore, the correct assertion that a derivation proceeding is conducted ex parte reflects the procedural rules governing these proceedings.