The PTAB has just designated multiple new opinions as "informative", including two cases from ex parte appeals. One of those decisions, ex parte Jung, involves the proper interpretation of “at least one of A, B, and C” as, by definition, meaning “at least one of A, at least one of B, and at least one of C.” The PTAB relied on the Federal Circuit's decision in SuperGuide (from 2004), even thought the applicant's specification did not even disclose A and B and C together (rather it only disclosed them as alternative options). This of course led the PTAB to enter a new ground of rejection for lack of written description.

Look for further posts on the implications of these decisions on patent drafting and prosecution strategy.