A new asymptotically optimal code for the positive integers

A new universal binary code for the positive integers is proposed as a modified version of M. Wang´s (see ibid., vol.34, p.324-6, Mar. 1988) flag encoding scheme. The codeword length of the new scheme is shorter than Wang´s, on an average, for large initial segments of the positive integers. The performance of the new scheme is also compared with that of other universal schemes. Furthermore, it is shown that an asymptotically optimal code can be achieved by modifying the new flag scheme such that the flag length varies dynamically