  We present the observations of a double-decker filament to study its
formation, triggering, and eruption physics. It is observed that the
double-decker filament was formed by splitting of an original single filament.
During the splitting process, intermittent bright point bursts are observed in
the filament channel, which resulted in the generation of the upper filament
branch. The eruption of the newly formed double-decker filament was possibly
triggered by two recurrent two-sided loop jets in the filament channel and the
continuous mass unloading from the upper filament body. The interaction between
the first jet and the filament directly resulted in the unstable of the lower
branch and the fast rising phase of the upper branch. The second jet occurred
at the same site about three hours after the first one, which further disturbed
and accelerated the rising of the lower filament branch. It is interesting that
the rising lower branch overtook the upper one, and then the two branches
probably merged into one filament. Finally, the whole filament erupted
violently and caused a large-scale coronal mass ejection, leaving behind a pair
of flare ribbons and two dimming regions on the both sides of the filament
channel. We think that the intermittent bursts may directly result in the
rearrangement of the filament magnetic field and therefore the formation of the
double-decker filament, then the recurrent jets further caused the fully
eruption of the entire filament system. The study provides convincing evidence
for supporting the scenario that a double-decker filament can be formed by
splitting a single filament into two branches.
