David Hill
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 Apr 21 comment Computing in quantum groups Ha. I almost gave this answer with a link to your website. Mar 10 awarded Organizer Mar 10 revised Irreducible representations in BGG category $\mathcal{O}$ over (finitely) direct sum of general linear Lie superalgebra removed ct.category-theory tag, added rt.representation-theory tag. Mar 10 suggested approved edit on Irreducible representations in BGG category $\mathcal{O}$ over (finitely) direct sum of general linear Lie superalgebra Mar 3 awarded Yearling Feb 18 comment Generalization of the sign representation to Hopf algebras @DenisNardin In the group case the determinant is $\pm 1$. This is not going to carry over in general. It would be helpful if to see a list of properties that one might want to see in such a sign representation (besides giving the sign rep. in the group case). Dec 8 answered Request for classical articles in representation theory Dec 5 comment Mystery behind ADE Dynkin diagram @JoshuaGrochow I suggest you read the answer to the question linked in Ben's comment. I believe the current question is treated very well there. Sep 3 revised Free $k[x_1, \dots, x_n]^{S_n}$-module? fixed typo Sep 3 comment What's the relation between half-twists, star structures and bar involutions on Hopf algebras? Sep 3 comment What's the relation between half-twists, star structures and bar involutions on Hopf algebras? The bar involution is an algebra automorphism defined by $\overline{E}=E$, $\overline{F}=F$ and $\overline{q}=q^{-1}$. The relation $[E,F]=(K^2-K^{-2})/(q-q^{-1})$ implies that $\overline{K}=K^{-1}$ since $\overline{[E,F]}=[E,F]$. I guess if the star is antilinear'' means take complex conjugates of coefficients, then, for $q$ a root of unity, this would be compatible. Sep 3 comment What's the relation between half-twists, star structures and bar involutions on Hopf algebras? Maybe I am misunderstanding what you mean by $U_qSL(2)_{\mathbb{C}}$. Is this the quantum group over $\mathbb{C}(q)$, or $U_qSL(2)\otimes_{\mathbb{Q}(q)}\mathbb{C}$ where $\mathbb{C}$ is regarded as a $\mathbb{Q}(q)$ module with $q$ acting as a scalar? Sep 3 comment What's the relation between half-twists, star structures and bar involutions on Hopf algebras? Are you sure both send $K\mapsto K$? My first thought was that they differ by the bar involution, but then one should be $K\mapsto K^{-1}$. Sep 2 answered Free $k[x_1, \dots, x_n]^{S_n}$-module? Sep 1 revised Constructing a simple $A$-module another typo Sep 1 revised Constructing a simple $A$-module fixed typo Sep 1 answered Constructing a simple $A$-module Aug 27 comment Generalized identities of (soluble) groups I don't understand your definition. If $a_1,\ldots,a_n\in G$, what does $x^{a_1}\cdots x^{a_n}$, $x\in G$ mean? Jul 14 comment What are the “tensor-closed” object of the BGG category $\mathcal{O}$ of a semisimple Lie algebra $\mathfrak{g}$? No, I was mistaken. I think one can probably show that the tensor product of a Verma module with an infinite dimensional module is not finitely generated. Jul 14 comment Decomposition of quadratic polynomials inti irreducible representations of affine group over a finit field @Thomas $V$ is not closed under addition. It is just a set.