The Japanese commissioner in Washington DC in the 1900's studying the American patent system said, "We have looked about us to see what nations are the greatest, so that we can be like them... We said, 'What makes the United States such a great nation?' and we investigated and found that it was patents, and we will have patents."
Conducting a thorough patent search is difficult, particularly for the novice. Patent searching is a learned skill. A novice in the United States could contact the nearest Patent and Trademark Depository Library (PTDL) and seek out search experts to help in setting up a search strategy.
When approached with this legal assertion, as a patent counselor for your client, you need insights to help you define and determine your defense. No, I am not: A patent is defined by its language, and many times, proper preparation for a Markman Hearing, or Claim Construction Hearing, can determine the summary judgment. If you are accused of infringing on a claim, you want to find ways to minimize the scope of the claim [on the other hand, if you are accusing, you want to broaden a claim's scope]. With IP Street, you can scrutinize a claim in various ways. Your patent is invalid: Since the USPTO granted the patent, the presumption is that all of its claims are valid. Anyone can challenge the validity of a patent (request re-examination) whether or not an infringement injunction has been made. [Normally, when the USPTO learns of an infringement lawsuit, out of due diligence, they open a re-examination case.] The quickest path to invalidate a patent is to identify prior art.