fixed linear from atva

examples/omitting/conference_linear_safe.spec

+Workflow
+
+forallmay x:X,p:P
+	True -> Conf += (x,p)
+forallmay x:X,p:P
+	!Conf(x,p) -> Assign += (x,p)
+forall x:X,y:X,p:P,q:P
+	(Conf(x,p) ∧ ¬ Conf(y,p) ∧ Assign(x,p) ∧ Assign(y,q)) -> Assign -= (y,q)
+forall x:X,p:P,r:R
+	(Assign(x,p) ∧ O(x,p,r)) -> Read += (x,p,r)
+forallmay y:X,x:X,p:P 
+	(Assign(x,p) ∧ Assign(y,p)) -> Comm += (x,y,p)
+
+Declassify
+
+O(x:X,p:P,r:R): ¬ Conf(xt:X,p:P)
+
+Target
+
+Comm(xt:X, yt:X, pt:P)
+
+Causality
+
+a:X