active terms N mark cons recip sqr N terms s N active sqr 0 mark 0 active sqr s X mark s add sqr X dbl X active dbl 0 mark 0 active dbl s X mark s s dbl X 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 terms X terms active X active cons X1 X2 cons active X1 X2 active recip X recip active X active sqr X sqr active X active s X s active X active add X1 X2 add active X1 X2 active add X1 X2 add X1 active X2 active dbl X dbl active X active first X1 X2 first active X1 X2 active first X1 X2 first X1 active X2 terms mark X mark terms X cons mark X1 X2 mark cons X1 X2 recip mark X mark recip X sqr mark X mark sqr X s mark X mark s X add mark X1 X2 mark add X1 X2 add X1 mark X2 mark add X1 X2 dbl mark X mark dbl X first mark X1 X2 mark first X1 X2 first X1 mark X2 mark first X1 X2 proper terms X terms proper X proper cons X1 X2 cons proper X1 proper X2 proper recip X recip proper X proper sqr X sqr proper X proper s X s proper X proper 0 ok 0 proper add X1 X2 add proper X1 proper X2 proper dbl X dbl proper X proper first X1 X2 first proper X1 proper X2 proper nil ok nil terms ok X ok terms X cons ok X1 ok X2 ok cons X1 X2 recip ok X ok recip X sqr ok X ok sqr X s ok X ok s X add ok X1 ok X2 ok add X1 X2 dbl ok X ok dbl X first ok X1 ok X2 ok first X1 X2 top mark X top proper X top ok X top active X active 1 terms 1 mark 1 cons 2 recip 1 sqr 1 s 1 0 0 add 2 dbl 1 first 2 nil 0 proper 1 ok 1 top 1 INNERMOST ./TRS/TRCSR/inn/Ex2_Luc02a_C.trs