Def b == if b false else true fi

is mentioned by

Def spanner(f;T;to;from) Def == (l:Edge(T). f(l) = f(inverse(l))) Def == & (i:|T|, l1,l2:Edge(T). Def == & ((l1  to(i)) Def == & ( Def == & ((l2  to(i))  l1 = l2  IdLnk  (f(l1))  (f(l2)))

[spanner]

In prior sections: bool 1 union mb event system 1 mb event system 3 mb event system 4

Try larger context: EventSystems IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html