Last updated 
Temporal operators
add-time
  pact
(add-time t s)  pact
(add-time t s)- takes t:time
- takes s: a
- produces time
- where a is of type integerordecimal
Add seconds to a time
Supported in either invariants or properties.
diff-time
  pact
(diff-time a b)  pact
(diff-time a b)- takes a:time
- takes b:time
- produces decimal
Time difference in seconds of a - b
Supported in properties only.