Opposition may only be filed on the grounds that:
Note that each single condition mentioned above forms an individual legal basis for objection to the maintenance of the patent. Consequently, each such condition is to be regarded as a separate ground of opposition (see G 1/95 and G 7/95).
The following allegations, for example, do not constitute grounds for opposition: that national rights of earlier date exist which put the patentability of the invention in question (see, however, H‑III, 4.5), that the proprietor of the patent is not entitled to the European patent, that the subject-matter of the patent lacks unity, that the claims are not supported by the description (unless it is also argued that the claims are so broadly worded that the description in the specification does not sufficiently disclose the subject-matter within the meaning of Art. 100(b)), that the form and content of the description or drawings of the patent do not comply with the provisions as to formal requirements as set forth in Rules 42 and Rule 46, or that the designation of the inventor is incorrect. Nor does the simple allegation that priority has been wrongly claimed constitute a ground for opposition. However, the matter of priority must be subjected to a substantial examination in the course of opposition proceedings if prior art is invoked in connection with a ground for opposition under Art. 100(a) in relation to which the priority date is of decisive importance (see G‑IV, 3 and F‑VI, 2).