If model checking shows that a property is satisfied, it can be relied upon that no execution of the system, no matter what the particular interleaving of events or the speeds of independent processes, can violate the property. The timeline is the thick horizontal bar close to the top of the drawing canvas. Time progresses to the right on the timeline. Along the timeline are vertical bars. These are marks which represent system execution steps, not clock ticks, since software model checking does not use a system clock.
Marks are the placed where events are attached.
The timeline editor tool is depicted in Figure 1 . These are non-deterministic events, typically input from users or external entities. These are events that are required in response to previous events and constraints that have been detected. It is an error if required events are not detected. In addition to events, there are also constraints.