theorem
  LSeg(p,G*(len G,1)+|[1,-1]|) meets Int cell(G,len G,0)
proof
  now
    take a = G*(len G,1)+|[1,-1]|;
    thus a in LSeg(p,G*(len G,1)+|[1,-1]|) by RLTOPSP1:68;
    thus a in Int cell(G,len G,0) by Th39;
  end;
  hence thesis by XBOOLE_0:3;
end;
