  The shuffle relation among multiple zeta values is algebraically expressed as
the shuffle algebra. In this paper, the shuffle algebra structure for multiple
zeta values is extended to a Hopf algebra structure, for which the key idea is
the lifting of the shuffle multiplication to Chen fractions as the function
multiplication. The linear span of Chen fractions can be equipped with a
locality Hopf algebra structure, and the pushforward of the coproduct gives us
the desired construction on the shuffle algebra.
