4.2.1.2.6 Combination Set (C-set)

Date Published

C-set classification is a special classification technique, providing a mechanism for searching combined features that are otherwise not easy to find by single symbols, resulting in more precise and efficient retrieval of technical information from the CPC.

C-set

C-sets are a combination of CPC symbols used for classifying combined technical features that cannot be adequately covered by the allocation of a single symbol.

Examples:

  • The C-Set (A, B) may denote a specific mixture of chemical compounds A and B.
  • The C-Set (A, B) can also denote a chemical compound A and its specific process of making B.

C-Sets can also define the relationship of related technical features.

  • Example: The C-Set (S1, S2, S3), displaying a specific order of symbols, may denote a specific order or sequence of operations S1, S2, S3 in a multi-step process.

A C-Set can also define:

  • a chemical compound and the specific process of making it
  • the technical features or materials of a particular method
  • a specific mixture of chemical compounds
  • the components of a formulation
  • the function of an ingredient
  • the different steps of a multistep process

Format

A C-Set:

  • comprises a group of at least two ranked valid CPC symbols (main-trunk classification symbols or indexing codes), separated by commas
  • brings together symbols from different groups within the same subclass or from different subclasses, in a certain order.


Example:

C05C9/005,

C05D9/02,

C05G3/0058

Base

subsequent

subsequent

rank 1

rank 2

rank 3

  • C05C9/005: The first symbol is designated as the “base symbol”, and has the Rank 1 in the database.
  • C05D9/02: The second symbol is designated as the “subsequent symbol”, and has the Rank 2 in the database.
  • C05G3/0058: Any further symbol, if present, is also designated as “subsequent symbol”, and has the Rank 3 or higher in the database.


Technologies

To ensure classification accuracy and consistency, C-Sets classification is authorised only in a limited number of CPC subclasses. The table in Annex III of the CPC guide lists those subclasses authorised for C-Sets allocation. As shown in the Table, not all groups within the authorized subclasses are allowed for C-Sets allocation.

A list of all areas of the CPC that allows the use of C-Sets can be found on the CPC website.

This list is updated if new areas are authorised to use C-Sets.