The phenomenon of the dark energy transition between the quintessence regime ( w > -1 ) and the phantom regime ( w < -1 ) , also known as the cosmological constant boundary crossing , is analyzed in terms of the dark energy equation of state .
It is found that the dark energy equation of state in the dark energy models which exhibit the transition is implicitly defined .
The generalizations of the the models explicitly constructed to exhibit the transition are studied to gain insight into the mechanism of the transition .
It is found that the cancellation of the terms corresponding to the cosmological constant boundary makes the transition possible .