Under Rule 42(1)(c) the applicant has to disclose the invention in such terms that the technical problem and its solution can be understood, and state any advantageous effects of the invention with reference to the background art. This technical problem constitutes in the first instance the single inventive general concept referred to in Art. 82, and therefore the common matter between the independent claims.
Therefore, if on closer examination, in view of the information contained in the description and the common general knowledge of the skilled person, it is evident that different independent claims solve different problems, then several inventive general concepts are present in the application contrary to the requirements of Art. 82.
Since the technical problem defined by the applicant no longer constitutes the common matter linking the independent claims, the examiner will then proceed to analyse if any special common matter in the sense of Rule 44(1) is present in the independent claims, i.e. identify, in the light of the application as a whole, any technical features of the independent claims that are the same or corresponding.
Features that are part of the common knowledge of the skilled person cannot constitute a special technical feature per se.
The principles of the problem-solution approach are to be applied when determining if, in view of the entire application as filed, some of the technical features of the independent claims are corresponding, i.e. if they solve the same technical problem and hence form part of the common matter.
For example a membrane and a diaphragm may solve the technical problem of "providing resilience" and hence are corresponding features.
If no common or special technical feature is present in the claims, then the application lacks unity because neither a technical relationship in the sense of Rule 44(1) is present between the independent claims, nor does the application entail a single general inventive concept in the sense of Art. 82.