1 | 16. i+1-||map( c. < 1of(c),a.2of(c) > ;C)|| = 0 1 NDA
(1of((map( c. < 1of(c),a.2of(c) > ;C) @ [ < p,nil > ])[i])
,hd(rev(2of((map( c. < 1of(c),a.2of(c) > ;C) @ [ < p,nil > ])[i])))
,1of([ < p,nil > ][(i+1-||map( c. < 1of(c),a.2of(c) > ;C)||)])) |