Def ForHdTl{A,f,k} h::t  as. g(h;t) == reduce(f;k;mapcons(h,t. g(h;t);as))

is not otherwise mentioned in this or prior sections.

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