Event driven interaction space where participants (agents, etc) are free register and unregister themselves. A participant should only register once in this type of space.
A participant is a software entity that is registered in order to receive the events that are emitted into the space. A participant is usually an agent, but not restricted to this type of software entity. It could be also a user-interface module.
A weak participant is participant that could be considered as not a first-order member of the space. When a participant is weak, it is not considered by functions such as #isPseudoEmpty(java.lang.UUID).