Def f  g == x:A. x  dom(f)  x  dom(g) & f(x) = g(x)  B(x)

is mentioned by

Thm* B,eq,g:Top.   g

[fpf-empty-sub]

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