11.1.15 Invalidity — Written Description / Claiming Requirements is a set of requirements set by the U.S. Patent and Trademark Office (USPTO) that must be met by applicants who wish to claim an invention as invalid. This includes providing a detailed written description of the invention, and a detailed argument made by the applicant that the invention is invalid. The requirements are broken down into two categories: 1. Written Description Requirements: These requirements involve providing a detailed written description of the invention that the applicant wishes to invalidate. This description must include a concise statement of the purpose and structure of the invention, and must include any known prior art that could be relevant to the claim. 2. Claiming Requirements: These requirements involve the applicant providing an argument for why the claim is invalid. This argument must include a clear explanation of why the invention does not meet all the requirements for patent ability, such as novelty, non-obviousness, and utility. The applicant must provide evidence to support their argument of invalidity, such as examples of prior art that demonstrates why the invention is not patentable.