What is the condition for entering the Patent Prosecution Highway (PPH)?

Entering the Patent Prosecution Highway (PPH) requires that at least one claim has been found allowable by the earlier office, which serves as a basis for expedited examination in the later office. This condition is fundamental to the PPH process, as it relies on the premise that the earlier examination has identified at least one claim as meeting the patentability criteria.

The PPH aims to streamline the patent application process by leveraging the findings from the first office where the application was examined. Thus, if at least one claim is deemed allowable, it indicates that the invention meets certain patentability requirements. This allows the subsequent office to expedite its examination process, potentially leading to a faster resolution for the applicant.

The other options do not accurately reflect the necessary condition for entering the PPH. For example, stating that all claims must be identical to those in a prior application misrepresents the flexibility allowed in PPH, where claims can be modified as long as they maintain some relation to the allowable claims. Similarly, the requirement that all claims need to be granted is too stringent; the focus is on having at least one allowable claim rather than granting all claims. The idea that substantive examination must have begun is also too vague and not directly tied to the PPH entry