3 problems

Let $\mathbb{O}$ be the base ring and let $\mathbb{K}$ be its field of fractions. Consider the Hopf algebras over $\mathbb{O}$ arising from the orders classified in the preceding t…

Let $r_{BD}$ be an $r$-matrix from the list in Lemma, and let $\mathfrak{g}$ be the corresponding Lie algebra. Twisted Lie bialgebra structures on $\mathfrak{g}$ corresponding to…

Let $\mathfrak{g}$ be a simple Lie algebra, let $G=\operatorname{Ad}(\mathfrak{g})$ be its adjoint group, and let $r_{DJ}$ be the Drinfeld–Jimbo $r$-matrix. For a Belavin–Drinfeld…