A construction of Hopf algebra cocycles for the double Yangian DY(S L 2 )
Abstract
We construct a Hopf algebra cocycle in the Yangian double
DY(S
L
2
)
, conjugating Drinfeld's coproduct to the usual one. To do that, we factorize the twist between two ``opposite'' versions of Drinfeld's coproduct, introduced in earlier work by V. Rubtsov and the first author, using the decomposition of the algebra in its negative and non-negative modes subalgebras.