theorem Th57:
  for G being BinContinuous TopaddGroup, A being dense Subset of G,
      a being Point of G holds A+a is dense
proof
  let G be BinContinuous TopaddGroup, A be dense Subset of G, a be Point of G;
  (+a).:A = A+a by Th16;
  hence thesis by TOPGRP_1:28;
end;
