and true X X and false Y false if true X Y X if false X Y Y add 0 X X add s X Y s add X Y first 0 X nil first s X cons Y Z cons Y first X Z from X cons X from s X and 2 1 true 0 false 0 if 3 1 add 2 1 0 0 s 1 first 2 1 2 nil 0 cons 2 from 1 FULL ./TRS/CSR/Ex15_Luc98.trs