Derivation of Petri net models of Ada tasking constructs involving time

Ada tasking constructs involving time are modeled by timed Petri nets. Such modeling is helpful in interpreting the (often) ambiguous semantics described in the Ada reference manual. Timed and conditional entry call models that shed light on determining implementable interpretations are presented. From a general selective wait model, it is shown how to apply Petri net reduction operations to derive other selective wait models