Mealey's (September 10, 2021, 1:37 PM EDT) -- WASHINGTON, D.C. — A petitioner for mandamus seeking to challenge a California federal judge’s ruling that an infringement defendant is not statutorily estopped from asserting patent invalidity based upon a disputed prior art reference failed to meet its “heavy burden of showing that the district court’s rulings” were “clearly and indisputably erroneous,” the Federal Circuit U.S. Court of Appeals ruled Sept. 9....