User blog comment:Nayuta Ito/Highly Nested Function/@comment-26428969-20151024084338

HNF(3,0,0,3) = HNF(0, -1, HNF(3, -1, 3, 3), 3) by rule 3, as B must not contain any 0s

HNF(3,3,3) = HNF(3,2,HNF(3,3,2)) = HNF(3,2,HNF(3,2,HNF(3,2,1))) =  HNF(3,2,HNF(3,2,HNF(3,2,HNF(3,2,HNF(3,2,0)))) =  HNF(3,2,HNF(3,2,HNF(3,2,HNF(3,2,HNF(3,2,HNF(3,2,-1) )))) always by rule 2, as there is no rule for trailing 0s

kinda ill-defined :/