Decomposable aggregation function

A decomposable aggregation function is like a machine that can break down a big challenge into smaller, easier pieces. Imagine having to clean up your whole bedroom at once. That might be overwhelming and seem impossible. But what if you broke it down into smaller tasks, like putting away the clothes and organizing your bookshelf? That might seem more do-able. That's exactly what a decomposable aggregation function does. It takes a big problem and breaks it down into smaller, easier pieces so that it can be solved faster and easier.