Exact category

In category theory, an **exact category** is a mathematical structure that generalizes the notion of exact sequences from abelian categories, allowing for a more flexible treatment in various contexts, including algebraic geometry and homological algebra. An exact category consists of the following components: 1. **Category**: It starts with a category \( \mathcal{E} \) that has a class of "short exact sequences" (which are typically triples of morphisms).