When we refactor the occurring entity branch, it was partially to discriminate between process and events. We can now start to add those events. The subbranch must be a child of "SBO:0000231 - occurring entity representation" and a sibbling of "SBO:0000375 - process". As first terms, I propose:
instantaneous modification of a participant quantity
==== instantaneous increase of a participant quantity
======== creation of a participant
==== instantaneous decrease of a participant quantity
We will have some more soon. But we can start to add them as we annotate BioModels entries.