This ground for opposition under Art. 100(c) refers back to Art. 123(2) and stipulates that the subject-matter of a European patent may not extend beyond the content of the application as filed.

Clarity is not a ground for opposition. Opposition proceedings are not designed as a procedure for generally amending (or revoking) patents that contain any kind of defect, and therefore opposition proceedings are not to be regarded as a continuation of examination proceedings.

The same substantive requirements apply in the opposition procedure regarding patentability pursuant to Art. 52 to Art. 57 as in the examination procedure. G‑I to G-VII will therefore also be applied in opposition proceedings.

In the unusual case where an opposition is limited to only a certain part of the patent, the opposition division has to limit its examination to the part opposed. However, if the opposition is directed only to an independent claim, the dependent claims are considered to be implicitly covered by the extent of the opposition and may be examined by the opposition division, provided their validity is prima facie in doubt on the basis of the information already available (see G 9/91).

Once the preparations for the examination of the opposition have been completed pursuant to Rule 79, the opposition division examines whether the grounds for opposition (see D‑III, 5) laid down in Art. 100 prejudice the maintenance of the European patent. The examination may also begin if a single admissible opposition has been withdrawn in the interim (see D‑VII, 5.3).