In the Dewey Decimal Classification (DDC) system, Standard Subdivisions are used to provide more detailed and specific categories and subcategories within each main class and subclass. Standard Subdivisions are used to refine and further define the topics and themes that are covered within each class and subclass, and they are typically represented by a combination of letters and numbers that are added to the decimal number that represents the main class or subclass.
For example, in the DDC system, the main class “Pure science” (class 5) is divided into a number of subclasses that are each assigned a unique decimal number. Within each subclass, Standard Subdivisions can be used to provide more specific categories and subcategories. For example, within the subclass “Mathematics” (class 510), Standard Subdivisions might be used to distinguish between different branches of mathematics, such as algebra, geometry, and trigonometry.
Standard Subdivisions are an important part of the DDC system, as they allow for a high level of detail and specificity within the classification system. They are used in conjunction with the main classes and subclasses, and the captions and notation schedules to create a comprehensive and detailed classification system that is used to organize and classify books and other materials according to subject matter in libraries around the world.