app app lt app s x app s y app app lt x y app app lt 0 app s y true app app lt y 0 false app app eq x x true app app eq app s x 0 false app app eq 0 app s x false app app member w null false app app member w app app app fork x y z app app app if app app lt w y app app member w x app app app if app app eq w y true app app member w z app 2 lt 0 s 0 0 0 true 0 false 0 eq 0 member 0 null 0 fork 0 if 0 FULL ./TRS/higher-order/Bird/BTreeMember.trs