Opposition systems are closely related to the patent granting procedure, and offer third parties an opportunity to oppose the grant of a patent, by giving notice of opposition to the granting authorities. In some states, there is a pre-grant opposition procedure, in others it is a post-grant procedure. Reasons for opposition may be that the invention is not new, does not involve an inventive step, is not susceptible of industrial application, is excepted from patentability, that the patent does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art, or that the subject-matter of the patent extends beyond the content of the application as filed, for instance.