Direct image with compact support

In the context of sheaf theory and derived categories in algebraic geometry or topology, the term "direct image with compact support" typically refers to the operation that takes a sheaf defined on a space and produces a new sheaf on another space, while restricting to a compact subset. More concretely, let's break this down: 1. **Sheaf**: A sheaf is a tool for systematically tracking local data attached to the open sets of a topological space.