Regulation 15—Unity of Invention, Claims in Different Categories.(1) Where a group of inventions is claimed, the requirement of unity of invention referred to in section 13 of the Law shall be deemed fulfilled only if there is a technical inter relationship between those inventions involving one or more of the same or corresponding special technical features.  The expression "special technical features" means those technical features which define the contribution which each of the inventions as claimed, or considered as a whole, makes over the prior art.(2)  The determination whether a group of inventions is so linked as to form a single general inventive concept shall be made without regard to whether the inventions are claimed in separate claims or as alternatives within a single claim.(3)  An application for a patent which includes an independent claim for—(a) a product, an independent claim for a process specially adapted for the manufacture of the product, and an independent claim for the use of the product; or(b) a process, an independent claim for an apparatus or means specifically designed for carrying out the process; or(c) a given product, an independent claim for a process specially adapted for the manufacture of the product and an independent claim for an apparatus or means specifically designed for carrying out the processshall be treated as being related to a group of inventions which are so linked as to form a single inventive concept.(4) Failure to comply with the requirement of unity of invention shall not be a ground for invalidation or revocation of a patent.