Braided Hopf Algebras

In braided tensor categories we show the Maschke's theorem and give the necessary and sufficient conditions for double cross biproducts and crossbiproducts and biproducts to be bialgebras. We obtain the factorization theorem for braided Hopf algebras; In symmetric tensor categories, we show the duality theorem and construct quantum double; In ordinary vector space category with ordinary twist, we obtain the relation between the global dimension, the weak dimension, the Jacbson radical, Baer radical of algebra $R$ and its crossed product R #_\sigma H. We also give the relation between the decompositions of comodules and coalgebras. We classify quiver Hopf algebras. We obtain all solutions of constant classical Yang-Baxter equation (CYBE) in Lie algebra $L$ with dim $L \le 3$. We also give the sufficient and necessary conditions for $(L, \hbox {[ ]}, \Delta_r, r)$ to be a coboundary (or triangular) Lie bialgebra.