Before revision: In this note we give, for a spectrally negative L\'evy process, a compact formula for the Parisian ruin probability, which is defined by the probability that the process exhibits an excursion below zero which length exceeds a certain fixed period r.
After revision: In this note we give, for a spectrally negative L\'evy process, a compact formula for the Parisian ruin probability, which is defined by the probability that the process exhibits an excursion below zero , with a length that exceeds a certain fixed period r.