Like Pmono, PmonoArtic plays one synth at a time (where successive events change the parameters of the existing synth node). PmonoArtic, however, allows events to re-articulate and supports staccato in the middle of a monophonic phrase.
If an event specifies a 'sustain' value shorter than the event delta, it means the synth should not sustain all the way through to the next event. In that case, the node will be released according to 'sustain' and the next event will start a new synth.
If sustain >= delta, the synth will play through and its parameters will change (just like Pmono).
Since sustain is calculated as ~dur * ~legato, this means ~legato < 1.0 causes re-articulation while ~legato >= 1.0 causes a slur.