Def P == InjCase(lem(P) ; true; false)

is mentioned by

Def simp_rec_rel Def == fun:'a. x:'a. f:'a'a. n:. (fun(0) = x Def == & (m:. m<n  fun(m+1) = f(fun(m))))

[hsimp_rec_rel]

In prior sections: hol hol bool

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