light of the reason for the change. In the unanimous opinion, Justice Kennedy explained that it was not whether prosecution history estoppel applied to amendments, but to what extent the amendment surrendered coverage of the claim. If the change was made to clarify a translation, for example, the inventor should suffer no reduction in rights. But if the change was made to keep the patent from overlapping with another patent, then the applicant will be presumed to have given up the right to complain about anything broader than the patent claim itself. In particular, the Court held that patentee's decision to narrow claims through amendment in order to comply with the Patent Act automatically assumes surrender of the territory between the original claim and the amended claim, i.e., a presumption of surrendering all equivalents for the particular claim limitation that was narrowed by the amendment. The Court thus placed the burden on the applicant as to showing what equivalents were not surrendered. The Court conceded, however, that there are some cases where the amendment cannot be viewed as surrendering a particular equivalent. "The equivalent may have been unforeseeable at the time of the application; the rationale underlying the amendment may bear no more than a tangential relation to the equivalent in question; or there may be some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question. In those cases the patentee can overcome the presumption that prosecution history estoppel bars a finding of equivalence." See also List of United States Supreme Court cases, volume 535 List of United States Supreme Court cases External links Address citing the case by Thomas O. Barnett, Assistant Attorney General, Antitrust Division, U.S. Department of Justice Papers "Patent Law: The Festo Case and the Doctrine of Equivalents", United States Congressional Research Service, July 25, 2002 United States Supreme Court cases United States Supreme Court cases of the Rehnquist Court United States patent case law 2002 in United States case law