Some definitions of interest.
lconnects	Def lconnects(p;i;j) Def == lpath(p) Def == & (||p|| = 0    i = j  Id) Def == & (||p|| = 0    i = source(hd(p)) & j = destination(last(p)))
	Thm* p:IdLnk List, i,j:Id. lconnects(p;i;j)  Prop
IdLnk	Def IdLnk == IdId
	Thm* IdLnk  Type
Id	Def Id == Atom
	Thm* Id  Type
assert	Def b == if b True else False fi
	Thm* b:. b  Prop
length	Def ||as|| == Case of as; nil  0 ; a.as'  ||as'||+1  (recursive)
	Thm* A:Type, l:A List. ||l||
	Thm* ||nil||
not	Def A == A  False
	Thm* A:Prop. (A)  Prop
null	Def null(as) == Case of as; nil  true ; a.as'  false
	Thm* T:Type, as:T List. null(as)
	Thm* null(nil)

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