4.2.1.2.6 Combination Set (C-set)

Also in this Chapter:

• ​​​​​​​​​​​​​​4.2.1.2.1 Structure of the CPC and 2000 Series
• ​​​​​​​4.2.1.2.2 Headings and Titles
• ​​​​​4.2.1.2.3 Definitions, Notes and Warnings
• 4.2.1.2.4 Function-Oriented and Application-Oriented Places
• 4.2.1.2.5 References​​​​​​​

• 4.2.1.2.7 CPC Revisions

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: 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.