active dbl 0 mark 0 active dbl s X mark s s dbl X active dbls nil mark nil active dbls cons X Y mark cons dbl X dbls Y active sel 0 cons X Y mark X active sel s X cons Y Z mark sel X Z active indx nil X mark nil active indx cons X Y Z mark cons sel X Z indx Y Z active from X mark cons X from s X active dbl X dbl active X active dbls X dbls active X active sel X1 X2 sel active X1 X2 active sel X1 X2 sel X1 active X2 active indx X1 X2 indx active X1 X2 dbl mark X mark dbl X dbls mark X mark dbls X sel mark X1 X2 mark sel X1 X2 sel X1 mark X2 mark sel X1 X2 indx mark X1 X2 mark indx X1 X2 proper dbl X dbl proper X proper 0 ok 0 proper s X s proper X proper dbls X dbls proper X proper nil ok nil proper cons X1 X2 cons proper X1 proper X2 proper sel X1 X2 sel proper X1 proper X2 proper indx X1 X2 indx proper X1 proper X2 proper from X from proper X dbl ok X ok dbl X s ok X ok s X dbls ok X ok dbls X cons ok X1 ok X2 ok cons X1 X2 sel ok X1 ok X2 ok sel X1 X2 indx ok X1 ok X2 ok indx X1 X2 from ok X ok from X top mark X top proper X top ok X top active X active 1 dbl 1 0 0 mark 1 s 1 dbls 1 nil 0 cons 2 sel 2 indx 2 from 1 proper 1 ok 1 top 1 INNERMOST ./TRS/TRCSR/inn/Ex3_2_Luc97_C.trs