is mentioned by

Thm* Q:(ABProp). (x:A. y:B. Q(x,y))  (f:(AB). x:A. Q(x,f(x)))

[ax_choice]

In prior sections: core

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