EPC: How Much Set Theory to be Applied by the Applicant when Preparing a Sequence of Divisional Applications?
How much set theory will have to be applied by the Applicant when preparing a sequence of Divisional Applications under the European Patent Convention? This question appears to be quite open as in Case T 1409/05 the Board of Appeal has just referred following questions to the Enlarged Board of Appeal:
"[...] Headnote: [...]
(1) In the case of a sequence of applications consisting of a root (originating) application followed by divisional applications, each divided from its predecessor, is it a necessary and sufficient condition for a divisional application of that sequence to comply with Article 76(1) EPC, second sentence, that anything disclosed in that divisional application be directly, unambiguously and separately derivable from what is disclosed in each of the preceding applications as filed?
(2) If the above condition is not sufficient, does said sentence impose the additional requirement (a) that the subject-matter of the claims of said divisional be nested within the subject-matter of the claims of its divisional predecessors?
or
(b) that all the divisional predecessors of said divisional comply with Article 76(1) EPC?[...]"
In this context, see also T 0039/03 referred to the Enlarged Board of Appeal in 2005. This matter concernes the question whether or not a divisional application which does not meet the requirements of Article 76(1) EPC because, at its actual filing date, it extends beyond the content of the earlier application, can be amended later in order to make it a valid divisional application.
Having regard to Article 8 of its Rules of Procedure, the Enlarged Board of Appeal has decided to consider the points of law referred to it by the Technical Board of Appeal 3.4.02 in case T 39/03 (G 1/05) and by the Technical Board of Appeal 3.4.03 in case T 1409/05 (G 1/06) in consolidated proceedings.
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Dipl.-Phys. Axel H Horns is Patentanwalt (German Patent Attorney),
European Patent Attorney as well as European Trade Mark Attorney. In particular, he is Member of:
Case T 1409/05 the Board of Appeal has just referred following questions to the Enlarged Board of Appeal: 
