is mentioned by

Def hd == l:'a List. if null(l) then arb('a) else head(l) fi	[hhd]
Def rep_list('a;l) == <n:. if n<||l|| then l[n] else arb('a) fi ,||l||>	[rep_list]

In prior sections: hol hol restr binder

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