Def bi-graph(G;to;from)
Def == i:|G|. 
Def == (lto(i).destination(l) = i
Def == & (G(source(l)))
Def == & (l  from(source(l)))
Def == & (lnk-inv(l)  from(i)))
Def == & (lfrom(i).source(l) = i
Def == & & (G(destination(l)))
Def == & & (l  to(destination(l)))
Def == & & (lnk-inv(l)  to(i)))

is mentioned

In prior sections: mb event system 7

IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html