The Birkhoff–Grothendieck theorem is a fundamental result in the field of lattice theory and universal algebra. It characterizes the representability of certain types of categories, especially in the context of complete lattice structures. **Statement of the theorem:** The Birkhoff–Grothendieck theorem states that a distributive lattice can be represented as the lattice of open sets of some topological space if and only if it is generated by its finitely generated ideals.