What is one permissible action you can take if you have evidence that claims in a pending application are invalid due to public prior use?

Filing a request for a protest is a permissible action when there is evidence that claims in a pending application are invalid due to prior public use. A protest allows third parties to submit relevant information that may affect the patentability of a pending application. This can include prior art or evidence such as public use or offers for sale that may negate the novelty or non-obviousness of the claimed invention.

In this context, the requester submits the evidence to the United States Patent and Trademark Office (USPTO) along with a statement detailing the relevance of the information. This action is specifically designed to inform the patent examiner about issues that could impede the granting of the patent, thus ensuring that only properly patentable claims are allowed to proceed.

Other options would not be appropriate for addressing concerns of invalidity due to public prior use. For example, a preissuance submission, while also allowing for submission of prior art, does not focus on invalidating claims based solely on public use; around public use, a protest is more targeted. Submitting a complaint to the applicant or withdrawing representation would not serve the purpose of actively contesting the validity of the application in the patent examination process.