declare
fun {Incorpore L1 L2}
   case L1
   of A|B then
      case L2 of H|T then
     if H == A then {Incorpore B T}
     else {Incorpore L1 T}
     end
      else false
      end
   else true
   end
end
fun {Apex LL}
   fun {Avant X L}
      fun {Apres B C}
     case C of H|T then
        if {Incorpore B H} then {Apres H T}
        else false
        end
     else true
     end
      end
   in
      case L of H|T then
     if {Incorpore H X} then
        if {Apres H T} then H|{Avant H T}
        else {Avant H T} end
     else nil end
      else nil end
   end
in
   case LL of H|T then
      case {Avant H T}
      of A|nil then true
      else false end
   else false
   end
end
{Browse {Incorpore [2 5 4] [3 2 8 2 6 5 3 4]}}
{Browse {Incorpore [1 2] [2 1]}}
{Browse {Apex [[3 5 2 4] [3 2 4] [5 3 4 2 6 3]]}}
{Browse {Apex [[3 5 2 4] [3 2 4] [5 3 4 2 6 4]]}}