A Formal Environment Model for Multi-Agent Systems - Formal Methods: Foundations and Applications - page 67

specification. Second, it is necessary to specify processes built using those events.
In this section we account for this first part.
Input and output events are all made from basic names. Hence, we first for-
mally define a set of names in order to have the corresponding events. The
definition below define such names, and Table 1 explains the events that arise.

Definition 2 (Environment Names). The environment names are defined
by the following set:

emit a ,stop a , beginning s ,stable s ,absent s ,
destroy s,m

ENames = {

a,n , ccn, done

|

}
Moreover, the set of environment events that immediately follow from ENames
is cal led EEvents.

a ∈ Actions, s ∈ Stimuli, m, n ∈ AgentIDs

Notice that names are primitive entities, even though they are denoted here with
subscripts and superscripts, which could suggest some sort of parametrization.
This writing style is merely for readability's sake.

Tabl e 1 . Informal description of events, divided in three categories according to their
origin and destination. The corresponding output or input events not shown merely
allow the ones described to work properly.

Event Informal description

Agent to environment

emit a Agent identified by n performs action a .

stop a Agent identified by n stops performing action a .

Environment to agent

beginning s

Delivery of stimulus s to the agent identified by n is beginning.

stable s

Delivery of stimulus s to the agent identified by n is stable.

ending s Delivery of stimulus s to the agent identified by n is ending.

absent s Delivery of stimulus s to the agent identified by n becomes

absent.

Environment to environment

destroy s,m
a,n

Requests the destruction of an action transformer that converts
action a from agent identified by n into stimulus s accepted by
the agent identified by m .

ccn Requests the creation of a new action transformer.

done Signals that an operation has terminated.

2.2 Operations

In order to exhibit dynamic behavior, the environment depends on operations
to modify its structures.