Before revision:  We illustrate their use for stochastic volatility asset price models driven by semimartingales. Finally, we prove the well-definedness of semimartingale Libor models given by a backward construction .
After revision:  This turns out to be very convenient in financial modeling in general. Especially it allows us to carefully discuss the question of well-definedness of semimartingale Libor models given by a backward construction .