reserve V for non empty RLSStruct;
reserve x,y,y1 for set;
reserve v for VECTOR of V;
reserve a,b for Real;

theorem
  for V being add-associative right_zeroed right_complementable
  non empty addLoopStr, u,v being Element of V
  ex w being Element of V st v - w = u
proof
  let V be add-associative right_zeroed right_complementable non empty
  addLoopStr;
  let u,v be Element of V;
  consider w being Element of V such that
A1: v + w = u by Lm2;
  take - w;
  thus thesis by A1;
end;
