poss:(ES{i}Prop{i'}), R:(possible-event{i:l}(poss)possible-event{i:l}(poss)Prop{i'}).
(EquivRel _1,_2:possible-event{i:l}(poss). R(_1,_2))
 (P:(possible-event{i:l}(poss)Prop{i'}), e:possible-event{i:l}(poss).
 (es-knows{i:l}
 (es-knows(poss; R; P; e)
 ( es-knows{i:l}
 ( es-knows(poss; R; (e.es-knows{i:l}(poss; R; P; e)); e)) 

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Definitions	t  T, P  Q, x:A. B(x), PossibleEvent(poss), f(a), False, A, x:AB(x), Prop, Type, ES, x,y. t(x;y), EquivRel x,y:T. E(x;y), Void, K(P)@e, Sym x,y:T. E(x;y), x:AB(x), P & Q, Trans x,y:T. E(x;y)
Lemmas	not wf, equiv rel wf, event system wf, possible-event wf