User LJR

6 votes

$\langle 2,x \rangle$ is a non-principal ideal in $\mathbb Z [x];\, $ $D[x]$ PID $\Rightarrow D$ field, for a domain $D$

answered Oct 23, 2014 at 13:21

4 votes

Accepted

What is the relationship between Cartan matrices and Coxeter matrices?

answered Mar 21, 2017 at 14:22

4 votes

Accepted

An identity about antipode in a Poisson Hopf algebra.

answered Jan 21, 2017 at 16:33

3 votes

Accepted

Questions about Haar integral for the group $GL_2(\mathbb{R})$.

answered Dec 26, 2013 at 9:31

3 votes

Accepted

How to show that $\pi \cot \pi \tau = \pi i - 2 \pi i \sum_{m=1}^{\infty} q^m$?

answered Sep 3, 2013 at 2:47

2 votes

Relations between Lie algebras and Lie coalgebras.

answered Feb 23, 2016 at 8:07

2 votes

Accepted

Is a universal enveloping algebra a Poisson algebra?

answered Feb 28, 2017 at 17:04

2 votes

How to prove an isomorphism related to a filtration.

answered Nov 29, 2018 at 14:07

1 vote

How to obtain the root $2 \alpha_6 + \alpha_1 + 2 \alpha_2 + 3 \alpha_3 + 2 \alpha_4 + \alpha_5$ in type $E_6$ root system by Weyl group action?

answered Dec 10, 2019 at 17:39

1 vote

Accepted

Quantum Serre relations and braided commutator.

answered Sep 19, 2016 at 13:49

1 vote

How to find the longest element in a double coset of a Weyl group using SageMath?

answered Jan 23, 2022 at 14:03

1 vote

Trying to understand Levi decomposition of a parabolic subgroup.

answered Apr 24, 2018 at 12:10

1 vote

How to generate a totally positive matrix randomly using software like Maple?

answered May 14, 2018 at 9:55

1 vote

Chromatic polynomials

answered May 16, 2019 at 9:22

1 vote

Accepted

How to show that $(\delta'f)(e)=\delta(\phi^* f)(e)$?

answered Oct 23, 2013 at 10:34

1 vote

Accepted

How to solve a recurrence equation with non-constant coefficients?

answered Jun 15, 2012 at 19:19

1 vote

Accepted

How to show that a local finite dimensional algebra is basic from definition?

answered Oct 9, 2014 at 7:08

1 vote

Accepted

How to assign the output of solve in mupad to a set of valuables?

answered Feb 16, 2014 at 11:18

1 vote

Algebraic Peter-Weyl theorem in the case of $G=SL_2$.

answered Aug 26, 2015 at 14:40

1 vote

Accepted

Solve a system of equations.

answered Jul 10, 2014 at 7:15

1 vote

Accepted

How to solve a first order partial differential equation?

answered Aug 2, 2014 at 8:22

1 vote

Accepted

Torus action and multigrading.

answered May 3, 2016 at 12:45

1 vote

Is the tensor product of two Yetter-Drinfeld modules a Yetter-Drinfeld module?

answered Jul 22, 2016 at 13:10

0 votes

How to make the vertex $0$ frozen?

answered Sep 1, 2016 at 7:39

0 votes

Hilbert Series of $\mathbb{C}^2$?

answered Oct 24, 2018 at 8:31

0 votes

Accepted

How to derive the formula $\{t_{ij}, t_{kl}\} = \sum_{a,b} (r^{ajbl} t_{ia}t_{kb} - r^{iakb} t_{aj}t_{bl})$?

answered Sep 6, 2016 at 13:59

0 votes

Accepted

How to show that $\alpha_{i_p}(s_{i_{p-1}} \cdots s_{i_1}(h)) = (s_{i_1} \cdots s_{i_{p-1}}(\alpha_{i_p}))(h)$?

answered Sep 27, 2014 at 3:39

0 votes

Accepted

Poisson actions defined in terms of coactions.

answered Feb 20, 2015 at 8:39

0 votes

Accepted

A computation for Manin triple.

answered Jun 5, 2015 at 2:34

0 votes

Questions about fundamental representations of $SL_3/U$.

answered Jul 18, 2015 at 12:40

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53 Answers

$\langle 2,x \rangle$ is a non-principal ideal in $\mathbb Z [x];\, $ $D[x]$ PID $\Rightarrow D$ field, for a domain $D$

What is the relationship between Cartan matrices and Coxeter matrices?

An identity about antipode in a Poisson Hopf algebra.

Questions about Haar integral for the group $GL_2(\mathbb{R})$.

How to show that $\pi \cot \pi \tau = \pi i - 2 \pi i \sum_{m=1}^{\infty} q^m$?

Relations between Lie algebras and Lie coalgebras.

Is a universal enveloping algebra a Poisson algebra?

How to prove an isomorphism related to a filtration.

How to obtain the root $2 \alpha_6 + \alpha_1 + 2 \alpha_2 + 3 \alpha_3 + 2 \alpha_4 + \alpha_5$ in type $E_6$ root system by Weyl group action?

Quantum Serre relations and braided commutator.

How to find the longest element in a double coset of a Weyl group using SageMath?

Trying to understand Levi decomposition of a parabolic subgroup.

How to generate a totally positive matrix randomly using software like Maple?

Chromatic polynomials

How to show that $(\delta'f)(e)=\delta(\phi^* f)(e)$?

How to solve a recurrence equation with non-constant coefficients?

How to show that a local finite dimensional algebra is basic from definition?

How to assign the output of solve in mupad to a set of valuables?

Algebraic Peter-Weyl theorem in the case of $G=SL_2$.

Solve a system of equations.

How to solve a first order partial differential equation?

Torus action and multigrading.

Is the tensor product of two Yetter-Drinfeld modules a Yetter-Drinfeld module?

How to make the vertex $0$ frozen?

Hilbert Series of $\mathbb{C}^2$?

How to derive the formula $\{t_{ij}, t_{kl}\} = \sum_{a,b} (r^{ajbl} t_{ia}t_{kb} - r^{iakb} t_{aj}t_{bl})$?

How to show that $\alpha_{i_p}(s_{i_{p-1}} \cdots s_{i_1}(h)) = (s_{i_1} \cdots s_{i_{p-1}}(\alpha_{i_p}))(h)$?

Poisson actions defined in terms of coactions.

A computation for Manin triple.

Questions about fundamental representations of $SL_3/U$.