Information and communication may be defined in relationship to the processes
that move the information from the beginning, or entry of the information into the channel, to its exit from the channel. A process is an action-medium that
moves an input presented to the process to the output, possibly assigning new values
to one or more output variables. We use the term process because of Church’s
thesis, widely believed to be correct [KMA82], which suggests that processes,
functions, and algorithms all describe the same phenomenon; all these models of
computation for most purposes are equivalent and one may describe using one of
these and at the same time satisfactorily also describe as effectively as if one were
using one of the other models.
Information may be defined [Los97] as
the values for all variables in the output of any process. This information
is about either the process, or the inputs to the process (the
context of the process), or both.