problem([]==>n:pnat=>nth(n,nil)=nil in int list,
sym_eval(normalize_term([reduction([1,1],[nth2,equ(int list,left)])]))then[elementary(intro(new[n])then[identity,wfftacs])],lambda(v0,su(su(lambda(v1,su(v2,[v1 of v0],[v2]))of lambda(n,axiom),[nth2 of v0],[v1]),[term_of(nth2)],[nth2])),
[
]).
