@ik(v:T) triggers local action a @i when P (x:A) v
== (vartype(i;x) r A) & e@i. (kind(e) = k) (valtype(e) r T)
== & e'@i. (kind(e') = locl(a)) (e:E. ((e <loc e') & kind(e) = k & ((P((x when e),val(e))))))
== & e@i. (kind(e) = k) ((P((x when e),val(e)))) e'@i.kind(e') = locl(a)