The role of patent claims

In [24] Lening and Cavicchi say about claims:

A claim is what an inventor is stating to be unique about the invention. The claims become the actual monopoly granted to the invention. Claims define the scope of protection granted to the invention.

A claim can be independent (it stands by itself and is not dependent on another claim) or dependent (it makes express reference to a previous claim and depends on it). In the IsNot patent application, claim 1 is an independent claim while claim 2 is a dependent claim. A patent may also contain descriptions of preferred embodiments but they just serve as illustration and may at most be used to interpret the claims. A patent may contain both independent and dependent claims and the question arises what an infringement of a patent means exactly.⁸The precise procedure for interpreting the claims in a patent seems to be an ``art'' and is a matter of debate among lawyers [4]. This is unsatisfactory from a software engineering perspective. The patent is "infringed" (violated) if any one or more of the claims (independent or dependent) are infringed.

The status of claims needs also further clarification in the light of the ``expression versus idea'' discussion given earlier in Section 8.1. The question being: what is an infringement? From the perspective of the software engineering life cycle (Section 3) the following questions need clarification:

• Is infringement possible during requirements engineering?
• Is infringement possible during design?
• Is infringement possible during implementation?
• Is infringement possible during testing?
• Is infringement possible during maintenance?

To be on the safe side, we have assumed in our patent-based software life cycle that the answer to all these questions is ``yes''. However, the nature of such infringements will be completely different, both in their description, appearance, and discovery.

During requirements engineering and design, only the intended behavior of the system is available. It is for instance, impossible to observe a running version of the software. Infringements can only be discovered by a deep semantic comparison between patent text and design documents.

During implementation, the desired behavior is coded as software program. Now it becomes possible to observe the behavior of the software by executing it on a computer. It also becomes possible to perform more syntactic comparisons between patent text and program text.

Software is both human-readable and computer executable, and this makes it unique among patentable artefacts.