active and true X mark X active and false Y mark false active if true X Y mark X active if false X Y mark Y active add 0 X mark X active add s X Y mark s add X Y active first 0 X mark nil active first s X cons Y Z mark cons Y first X Z active from X mark cons X from s X active and X1 X2 and active X1 X2 active if X1 X2 X3 if active X1 X2 X3 active add X1 X2 add active X1 X2 active first X1 X2 first active X1 X2 active first X1 X2 first X1 active X2 and mark X1 X2 mark and X1 X2 if mark X1 X2 X3 mark if X1 X2 X3 add mark X1 X2 mark add X1 X2 first mark X1 X2 mark first X1 X2 first X1 mark X2 mark first X1 X2 proper and X1 X2 and proper X1 proper X2 proper true ok true proper false ok false proper if X1 X2 X3 if proper X1 proper X2 proper X3 proper add X1 X2 add proper X1 proper X2 proper 0 ok 0 proper s X s proper X proper first X1 X2 first proper X1 proper X2 proper nil ok nil proper cons X1 X2 cons proper X1 proper X2 proper from X from proper X and ok X1 ok X2 ok and X1 X2 if ok X1 ok X2 ok X3 ok if X1 X2 X3 add ok X1 ok X2 ok add X1 X2 s ok X ok s X first ok X1 ok X2 ok first X1 X2 cons ok X1 ok X2 ok cons X1 X2 from ok X ok from X top mark X top proper X top ok X top active X active 1 and 2 true 0 mark 1 false 0 if 3 add 2 0 0 s 1 first 2 nil 0 cons 2 from 1 proper 1 ok 1 top 1 FULL ./TRS/TRCSR/Ex15_Luc98_C.trs