Q) Indefinite Claim (10.03.49a)

ANSWER: (D) is the correct answer. See MPEP § 2173.05(c), under the heading “Open-Ended Numerical Ranges.” Paraphrasing the explanation therein, when an independent claim recites a composition comprising “at least 20% iron” and a dependent claim sets forth specific amounts of non-iron ingredients which add up to100%, apparently to the exclusion of iron, an ambiguity is created with regard to the “at least” limitation unless the percentages of the non-iron ingredients are based on the weight of the non-iron ingredients. On the other hand, a composition claimed to have a theoretical content greater than 100% (i.e., 20-80% of iron, 20-80% of gallium, and 1-25% of copper) is not necessarily indefinite simply because the claims may be read in theory to include compositions that are impossible in fact to formulate. Here, because the invention is a non-theoretical alloy, the sum of the claimed constituents cannot exceed 100% unless the percentage is based on weight. In (D), the sum of elements (B) and (C)is 81% by volume, leaving only 19% for iron. Claim 1, however, requires “at least 20% iron,” rendering Claim 2 ambiguous as to the percentage of element A. (A) is incorrect. The sum of gallium and copper components is 80%, leaving a possible 20% of the composition for element iron. Claim 1 requires “at least 20% iron,” which includes 20% iron. Therefore, the sum of iron, gallium and copper components in Claim 2 is 100%. (B) is incorrect. “At least 20% iron” includes 21% iron, “at least 10% gallium includes 11% gallium, and “at least 10% copper includes 10.01% copper. (C) is incorrect. “At least 20% iron” includes 20% iron, “at least 10% gallium includes 10% gallium, and “at least 10% copper” includes 10% copper. (E) is incorrect because Claim 1 uses the open transition phrase “comprising,” which permits additional elements to be added to the composition. Nothing in the problem indicates that an additional component, silver, cannot be added to the composition.