In a case in which a single priority is claimed for a given application and a number of features of a claim of said application are generalisations of specific features disclosed in the priority document, a partial priority is to be acknowledged, as long as it is possible to conceptually identify, by a comparison of the claimed subject-matter with the disclosure of the priority document, a limited number of clearly defined alternative subject-matters, including among the alternatives the specific embodiments which are directly and unambiguously derivable from the priority document. In order for this condition to be met, it is not necessary that the clearly defined alternative subject-matters are spelt out as such in the application, nor that the word "or" actually occurs (see point 4.5.12).

This condition extends to the case of multiple priorities. In that case, a comparison with the disclosure of each of the priority documents is necessary and for each of the clearly defined alternative subject-matters the earliest priority from which the alternative subject-matter is directly and unambiguously derivable is acknowledged (see point 4.5.13).