from X cons X from s X sel 0 cons X XS X sel s N cons X XS sel N XS minus X 0 0 minus s X s Y minus X Y quot 0 s Y 0 quot s X s Y s quot minus X Y s Y zWquot XS nil nil zWquot nil XS nil zWquot cons X XS cons Y YS cons quot X Y zWquot XS YS from 1 1 cons 2 1 s 1 1 sel 2 1 2 0 0 minus 2 1 2 quot 2 1 2 zWquot 2 1 2 nil 0 FULL ./TRS/CSR/Ex4_7_37_Bor03.trs