👉 In mathematics, a sheaf is a category that provides a way to define functors between various categories. Sheaves are used in many areas of mathematics, including algebraic geometry, homological algebra, and algebraic topology. A sheaf on a topological space X is a collection of objects (or "sheaves") called "sheaves" such that for each point x in X, the set of all maps from x to some other point y is an object of the category Set.
