In the context of patent applications, what must be addressed if a limitation was added after a rejection due to obviousness?

In the context of patent applications, particularly when dealing with amendments made after receiving a rejection based on obviousness, the principle of claim differentiation is crucial. If a limitation was added to overcome an obviousness rejection, it is essential to retain that limitation to ensure that the claims align with the support established in the original application.

The idea that a limitation cannot be retrieved if it has been deliberately given up reflects the doctrine that once a claim element is removed or surrendered during prosecution, it generally cannot be easily reinstated without risking the integrity of the application or introducing new matter. This aligns with the notion that patent applicants cannot selectively revive or reclaim abandoned features of a claim once they have been explicitly removed or surrendered.

Thus, retaining the limitation added to respond to the rejection is critical in addressing the examiners' concerns and maintaining the application's validity in light of previous rejections based on the obviousness standard. This understanding is foundational in navigating the complexities of patent prosecution and the implications of claim amendments.