3 (iii) software; (iv) methods, systems, schemes, discoveries and scientific theories as also abstractions of pure form that do not solve a material problem or do not provide a tangible technical solution, notwithstanding the protection of practical applications that incorporate them to meet the requirements of Article 4; (v) pharmaceutical, veterinary, cosmetic and food products. (2) Patents and inventors’ certificates obtained contrary to paragraph (1) shall be null and void. 9. The President of the Republic may decree the exclusion from patentability, either provisionally or definitively, of certain categories of invention where required by the vital interests of education or teaching, public health, the economy or national defense. 10. The protection afforded to a patent or an inventor’s certificate shall be 15 years as from the filing date of the application. However, if the national interest so demands and the invention is worked in the country in a serious and satisfactory manner, an additional term of five years may be afforded to the patentee or licensee or to the holder of the inventor’s certificate, at such person’s request. 11. A certificate of addition shall terminate together with the patent or inventor’s certificate. Section 2 Right to a Patent or an Inventor’s Certificate 12.—(1) Subject to Article 16 and Article 28(1), the right to a patent or an inventor’s certificate shall belong to the inventor or his successor in title. (2) The person who first files an application for a patent or an inventor’s certificate or who first validly claims priority in respect of an application for a patent or an inventor’s certificate concerning the same invention shall be considered, subject to Articles 14, 15 and 16, the inventor or his successor in title. 13. Where an invention is the result of collaboration between a number of persons, the right to the patent or the inventor’s certificate shall belong collectively to those persons or their successors in title. However, a person who has simply given his assistance in the execution of the invention without contributing a decisive inventive activity shall not be considered an inventor or joint inventor. 14. If essential elements of an application for a patent or inventor’s certificate or of a patent or inventor’s certificate have been taken by the applicant from the results of work or research by some other person without the consent of that latter person, with respect either to the borrowing or to the filing of the corresponding application, the person injured by such unlawful usurpation may institute legal proceedings to obtain transfer to himself of the application or the patent or the inventor’s certificate. 15.—(1) The true inventor shall have the right to be mentioned as such in the patent or inventor’s certificate. (2) The provision under paragraph (1) may not be modified by contract.