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.
and 
) showing a strong dependency.
When the object is in state 
in the lower track, the transition 
becomes impossible. This is indicated by conditioning this transition with [NOT Y].
