We introduce two constructions of a coassociative comultiplication in the algebra of phrases in a given alphabet. As a preliminary step we give two constructions of a pre-Lie comultiplication in the module generated by words.
@article{hal-00105678,
author = {Turaev, Vladimir},
title = {Coalgebras of words and phrases},
journal = {HAL},
volume = {2004},
number = {0},
year = {2004},
language = {en},
url = {http://dml.mathdoc.fr/item/hal-00105678}
}
Turaev, Vladimir. Coalgebras of words and phrases. HAL, Tome 2004 (2004) no. 0, . http://gdmltest.u-ga.fr/item/hal-00105678/