Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
An illustration of queries. Query (1) (2) (4) (5) can be performed by coupling two labels as illustrated in the brown-dashed rectangle. Since query (3)(6)(7)(8)(9) involves path constructions, a flow of path construction for path h → g → a → d → c is illustrated outside the brown-dashed rectangle.
