For any 1-reduced simplicial set K we define a canonical, coassociative
coproduct on \Om C(K), the cobar construction applied to the normalized,
integral chains on K, such that any canonical quasi-isomorphism of chain
algebras from
\Om C(K) to the normalized, integral chains on GK, the loop group of K,
is a coalgebra map up to strong homotopy. Our proof relies on the operadic
description of the category of chain coalgebras and of strongly homotopy
coalgebra maps given in math.AT/0505559.Comment: 28 pages. This revised version incorporates operadic techniques
developed in math.AT/050555