is mentioned by

Thm* r1:(T1T1Prop), r2:(T2T2Prop). Thm* T1 = T2 Thm*  Thm* (x,y:T1. r1(x,y)  r2(x,y)) Thm*  Thm* WellFnd{i}(T1;x,y.r1(x,y))  WellFnd{i}(T2;x,y.r2(x,y))	[wellfounded_functionality_wrt_implies]
Def WellFnd{i}(A;x,y.R(x;y)) Def == P:(AProp). (j:A. (k:A. R(k;j)  P(k))  P(j))  {n:A. P(n)}	[wellfounded]

In prior sections: core

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