What are the arrows on the UML Use Case diagram picture?

In UML Use Case diagrams, arrows are used to denote various relationships between elements:

• Association — a simple line showing interaction between an actor and a use case.
• Include — a dashed arrow with the label <<include>>, indicating that one use case always invokes another.
• Extend — a dashed arrow with the label <<extend>>, showing that one use case can extend the behavior of another under certain conditions.
• Generalization — an arrow with a hollow triangle at the end, representing inheritance between actors or use cases.

Thus, arrows in the diagram indicate the types of connections and dependencies between system elements.