Function main (TPN , Markings bad)
Where is a TPN
bad is a set of bad markings.
Let     be the set of controllable transitions of     and
  the initial state class of   .
If     then
   {Controller does not exist}
   return
end if
for all do
  
end for
;
;
;
;
;
is a fictitious transition whose time variable is fixed at .
Algorithm 1: On-the-fly algorithm for the safety control of TPN-Part I.