Does a compulsory, non-frivolous counterclaim of patent infringement confer appellate subject matter jurisdiction on this court?
Yes. “Because MTW’s compulsory counterclaim for patent infringement is a separate, nonfrivolous claim, having its own § 1338 jurisdictional basis independent of the jurisdictional basis of the complaint, the district court’s subject matter jurisdiction in this case was based in part on § 1338. Accordingly, this court would have appellate subject matter jurisdiction over an appeal from a final judgment in this case, 28 U.S.C. § 1295, and thus has appellate subject matter jurisdiction over the appeal from the present interlocutory order. 28 U.S.C. § 1292.”
