In case it is not valid, you get a counterexample. See details of ctldc model checkin in separate manaual. The automaton will be in one of following form. This command is used internally by ctldc model checker. Generates a file containing SPIN never-claims format description of the automaton for the property.
Horizontal axis is time.
There is one row for each propositional variable. Value 0 indicates false and value 1 indicates true. This spans an interval of lenght 2 with time positions 0,1,2. P is true at times 0 and 1 and false at 2. For a detailed specification examples see files in the examples subdirectory of the distribution.