Report Number: CS-TR-91-1360
Institution: Stanford University, Department of Computer Science
Title: Sooner is safer than later.
Author: Henzinger, Thomas A.
Date: May 1991
Abstract: It has been repeatedly observed that the standard
safety-liveness classification of properties of reactive
systems does not fit for real-time properties. This is
because the implicit "liveness" of time shifts the spectrum
towards the safety side. While, for example, response--that
"something good" will happen, eventually--is a classical
liveness property, bounded response--that "something good"
will happen soon, within a certain amount of time--has many
characteristics of safety. We account for this phenomenon
formally by defining safety and liveness relative to a given
condition, such as the progress of time.