👉 Directories in mathematics are collections of mathematical objects, such as groups, rings, vector spaces, or modules, organized in a structured way to facilitate study, comparison, and application. These directories often consist of categories like isomorphism classes, subdirectories based on properties (e.g., finite vs. infinite), or specific constructions (e.g., free modules). For example, the group of integers modulo n forms a direct product of cyclic groups for each divisor of n, while vector spaces are categorized by their dimension or basis type. Directories enable mathematicians to isolate and analyze specific behaviors, prove theorems more effectively, and build connections between seemingly distinct areas of mathematics by highlighting shared structures or relationships.