Recent work on the automatic generation of frame axioms from action specifications that have complete fluent change specifications is extended to extract action invariants. An action invariant expresses a property that is preserved by all actions of that class. The extraction is achieved by combining automatically generated frame axioms and the original action axioms relativised to those states...

rate of perinatal HIV transmission and to be beneficial in treating early HIV infection. However, the implications of these results for postexposure prophylaxis are uncertain. The short-term toxicity of ZDV in HCWs primarily has been gastrointestinal discomfort and fatigue. In 1990, the Public Health Service (PHS) concluded that a recommendation could not be made for or against the use of ZDV p...