> > I think, what you intend to say is clearer with 4 state system {NE, E} > > * {NV, V} = {(NE, NV), (NE, V), (E, NV), (E, V)} where (NE, V) is > > unreachable. Let's name them S1, S2, S3, S4 respectively. > [...] > > Notice that there are no edges to and from S2. > > So why list it as a possible state?
For the sake of combinatorics. :)
Just because there are 2^n combinations of n boolean values does not mean there are 2^n actual meaningful states. That's why we have CHECK constraints.
