UDC, or Universal Decimal Classification, is a system for organizing and classifying library materials based on their subject matter. The notational system of UDC consists of a series of decimal numbers and symbols used to represent the various categories and subcategories into which library materials are organized.
Each number in the notation represents a different category or subclass, and the relationships between the categories are indicated by the placement of the numbers. For example, a book about the history of agriculture might be classified using the notation “63:631,” which would indicate that it is a book about the history of agriculture, which is a subclass of “Agriculture,” which is a subclass of “Technology (applied sciences).”
In addition to decimal numbers, UDC also uses a variety of symbols to represent different types of relationships between categories, such as the use of brackets to indicate that a category is a subcategory of another category.
Overall, the UDC notation system is designed to be concise and efficient, while also providing a high degree of specificity and detail in the classification of library materials.