A simple point process (or SPP) is an almost surely increasing sequence of strictly
positive, possibly infinite random
variables which are strictly increasing
as long as they are finite and whose almost sure limit
is .
Symbolically, then, an SPP is a sequence
of
-valued random variables defined on a probability
space
such that
1. ,
2. ,
3. .
Here,
and for each
,
can be interpreted as either the time point at which the
th recording of an event takes place
or as an indication that fewer than
events occurred altogether if
or if
, respectively (Jacobsen 2006).