The case law of the boards of appeal is based on a narrow concept of novelty, i.e. the disclosure of a prior document does not include equivalents of the features which are explicitly or implicitly disclosed; equivalents can only be taken into account when it comes to considering inventive step (T 517/90). This narrow concept of novelty, which excludes equivalents, is of particular importance for the application of Art. 54(3) EPC. In T 167/84 (OJ 1987, 369) the board commented that conflicting applications within the meaning of Art. 54(3) EPC 1973 were included in the state of the art solely from the point of view of novelty, but were considered in the light of their "whole contents". In order to mitigate the harsh effects of the "whole contents approach", its application was confined to novelty. Further, in order to reduce the risk of "self-collision", it had always been considered justified to adopt a strict approach to novelty. For this reason, the Guidelines expressly stated that "when considering novelty, it is not correct to interpret the teaching of a document as embracing well-known equivalents which are not disclosed in the document; this is a matter of obviousness" (Guidelines G‑VI, 2 – November 2015 version). According to the case law of the boards of appeal the "whole contents" of an earlier document did not also comprise features which were equivalents of features in the later document (see also T 928/93, T 1387/06).
In T 652/01 the appellant was of the opinion that although the relevant prior-art document did not explicitly mention a particular feature, that feature could be derived from the document by applying the document's teaching mutatis mutandis. The appellant had referred to T 952/92 (OJ 1995, 755), which, in its first headnote, stated that "availability" within the meaning of Art. 54(2) EPC 1973 involved not only availability of the disclosure but also availability of information accessible and derivable from the disclosure, which meant that "derivable equivalents" were included. However, the board held that, when reading the cited phrase from T 952/92 in the context of the present decision, it was clear that the term "derivable" had been employed in the sense of "obtainable by chemical analysis of a sample" and that it was used with the same restriction as expressed in opinion G 1/92 (OJ 1993, 277), namely that it had to be "directly and unambiguously derivable".