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1 vote
0 answers
25 views

Finiteness of results in Connes-Kreimer approach

Remark: Although this is technically a physics-related post, the content heavily relies on pure mathematics, so I deemed it more appropriate here. When reading the papers by Connes and Kreimer (e.g. [...
NDewolf's user avatar
  • 1,713
1 vote
1 answer
56 views

Comultiplication on the tensor algebra

Let $k$ be a commutative base ring. We have a category $\operatorname{Mod}_k$ of $k$-modules and a category $\operatorname{grMod}_k$ of $\mathbb{Z}$-graded $k$-modules. Both of these have monoidal ...
Brendan Murphy's user avatar
1 vote
1 answer
65 views

Left ideals of group algebra $K[\mathbb H]$

I've been studying Hopf-Galois theory, and while writing by myself certain example, I came up with this question: Let $K$ be a field, and $\mathbb H$ the quaternion group. Is $K[\mathbb H]$ the only ...
Alejandro Bergasa Alonso's user avatar
1 vote
0 answers
19 views

$T(z) e^{-\partial_z} $ for Yangian is a Manin matrix

Let $T(u)$ be the generating matrix of the Yangian $Y(\mathfrak{gl}_n)$ of $\mathfrak{gl}_n$. So we have the identity $[T_{ij}(u),T_{kl}(v)]=\frac{1}{u-v}(T_{kj}(u)T_{il}(v)-T_{kj}(v)T_{il}(u))$. We ...
Asav's user avatar
  • 135
1 vote
0 answers
119 views

Hopf "algebroid" structure of a groupoid convolution algebra?

To male thinks simple as possible, lets say we have a discrete group $G.$ Then the then the group algebra $\mathbb{C}[G]$ (of finitely supported complex valued functions on $G$) has a convolution and ...
Bumblebee's user avatar
  • 18.4k
0 votes
1 answer
34 views

Showing that $U(\mathfrak{sl}_2)$ is a coalgebra

We know that there is a coalgebra structure on $U(\mathfrak{sl}_2)$ as follows for any $z\in \mathfrak{sl}_2$: $$\Delta(z)=1\otimes z+z\otimes 1, \qquad \epsilon(z)=0.$$ Can someone be so kind to ...
user510716's user avatar
6 votes
1 answer
61 views

Commutativity up to scalar implies commutativity in an algebra

Let $A$ be a (not necessarily commutative) algebra over a field $k$. Suppose that for all $a,b\in A$, we have $kab=kba$, i.e. commutativity up to scalar. Show that then $A$ is commutative. In the ...
Christoph Mark's user avatar
1 vote
1 answer
63 views

A certain decomposition of a semisimple Hopf algebra

$\newcommand{\Irr}{\mathrm{Irr}}$ Let $H$ be a finite-dimensional semisimple Hopf algebra over an algebraically closed field $k$, and let $\Irr(H)$ be the set of (choices of representatives of) ...
Jo Mo's user avatar
  • 2,075
0 votes
0 answers
37 views

Suggestion of research papers

I’m trying to find the research papers related to Hopf algebra over non commutative polynomial rings O( M_n(H)) to get concrete understanding about it. But unfortunately I couldn’t find any ...
Sania Asif's user avatar
4 votes
1 answer
830 views

group-like elements of a Hopf algebra and the group algebra

Suppose we are given a $n$-dimensional Hopf algebra $H$ over field $\mathbb K$. I want to prove that $H$ contains n distinct group-like elements if and only if there exists a group $G$ such ...
Nikita's user avatar
  • 1,087
3 votes
0 answers
104 views

Introductory text on Hopf algebras

Is there an introductory (but as complete as possible) text on Hopf algebras like Abe or Sweedler but working when possible over arbitrary commutative rings instead fields? "Like Abe or Sweedler" ...
A.G's user avatar
  • 1,423
5 votes
1 answer
545 views

An R-matrix in a quasitriangular Hopf algebra

I am new to the theory of Hopf algebra. So I am sorry if the following question has really trivial answer. Suppose that we have a quasi triangular Hopf algebra with the universal R-matrix $R$. It ...
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