The PCT does not define what is meant by "invention", but Rules 39 and 67 contain a list of subject-matter for which the ISA or IPEA is not required to carry out an international search or an international preliminary examination, respectively (see also GL/PCT‑EPO B‑VIII, 2). The Agreement between the EPO and WIPO in relation to the functioning of the EPO as an International Authority under the PCT indicates the subject-matter which the EPO is not required to search or examine, and according to its Art. 4 and Annex C the discretion not to search or examine is exercised by the EPO as ISA and IPEA only to the extent that such subject-matter is not searched under the provisions of the EPC, specifically Art. 52(2) EPC, Art. 52(3) EPC, Art. 53(b) EPC and Art. 53(c) EPC.