(VAR X Y Z) (RULES __(__(X,Y),Z) -> __(X,__(Y,Z)) __(X,nil) -> X __(nil,X) -> X U11(tt) -> tt U21(tt) -> U22(isList) U22(tt) -> tt U31(tt) -> tt U41(tt) -> U42(isNeList) U42(tt) -> tt U51(tt) -> U52(isList) U52(tt) -> tt U61(tt) -> tt U71(tt) -> U72(isPal) U72(tt) -> tt U81(tt) -> tt isList -> U11(isNeList) isList -> tt isList -> U21(isList) isNeList -> U31(isQid) isNeList -> U41(isList) isNeList -> U51(isNeList) isNePal -> U61(isQid) isNePal -> U71(isQid) isPal -> U81(isNePal) isPal -> tt isQid -> tt isQid -> tt isQid -> tt isQid -> tt isQid -> tt )