| Definitions |  x:A. B(x), P   Q,  b, Rframe?(x1), t  T, Rframe-loc(x1), false , true, if b t else f fi, Realizer, Unit, False,  , Prop, , left  right, @loc x initially v:T, @loc only events in L change x:T, only events in L send on lnk with tag, @loc effect knd(v:T) x := f State(ds) v , sends knd(v:T) on l:tagged(g,State(ds),v):dt, @loc precondition for a(v:T):P State(ds) v, @loc: k writes only members of L, @loc: k sends only on links in L, @loc: only members of L read x |