"Finite dimensional representations of Sl(2)"의 두 판 사이의 차이

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<h5>introduction</h5>
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==introduction==
  
* http://qchu.wordpress.com/2010/03/07/walks-on-graphs-and-tensor-products/
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* [[affine sl(2)]]
* http://mathoverflow.net/questions/17197/how-does-this-relationship-between-the-catalan-numbers-and-su2-generalize
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* [[quantum sl(2)]]
* [[affine sl(2) $A^{(1)} 1$]]
 
* [[search?q=quantum%20sl(2)&parent id=5522041|quantum sl(2)]]
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 2em; margin: 0px;">specialization</h5>
 
 
 
*  Cartan matrix<br><math>\mathbf{A} = \begin{pmatrix} 2 \end{pmatrix}</math><br>
 
*  root system<br><math>\Phi=\{\alpha,-\alpha\}</math><br>
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 2em; margin: 0px;">representation theory</h5>
 
 
 
*  integrable weights and Weyl vector<br><math>\omega=\frac{1}{2}\alpha</math><br><math>\rho=\omega</math><br>
 
*  there is a unique k+1 dimensional irreducible module <math>V_k</math> with the highest integrable weight <math>\lambda=k\omega</math><br>
 
 
 
*  Weyl-Kac formula<br><math>\operatorkame{ch}L(k\omega)=\frac{e^{(k+1)\omega}-e^{-(k+1)\omega}}{e^{\omega}-e^{-\omega}}=e^{k\omega}+e^{(k-2)\omega}+\cdots+e^{-k\omega}</math><br>
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 3.428em; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; color: rgb(34, 61, 103); font-family: 'malgun gothic', dotum, gulim, sans-serif; font-size: 1.166em; background-image: ; background-color: initial; background-position: 0px 100%;">character formula and Chebyshev polynomial of the 2nd kind</h5>
 
 
 
* <math>U_{n+1}(x) & = 2xU_n(x) - U_{n-1}(x)</math><br> U_0[x]=1<br> U_1[x]=2 x<br> U_2[x]=-1+4 x^2<br> U_3[x]=-4 x+8 x^3<br>
 
*  character evaluated at an element of SU(2) with the eigenvalues e^{i\theta}, e^{-i\theta} is given by the Chebyshev polynomials<br><math>U_k(\cos\theta)= \frac{\sin (k+1)\theta}{\sin \theta}</math><br>
 
* <math>w=e^{i\theta}</math>, <math>z=w+w^{-1}=2\cos\theta</math><br><math>p_k(z)=\frac{w^{k+1}-w^{-k-1}}{w-w^{-1}}</math><br><math>p_{0}(z)=1</math><br><math>p_{1}(z)=z</math><br><math>p_{2}(z)=z^2-1</math><br><math>p_{3}(z)=z^3-2z</math><br><math>p_k(z)^2=1+p_{k-1}(z)p_{k+1}(z)</math><br>
 
 
 
 
 
 
 
 
 
 
 
<h5>Hermite reciprocity</h5>
 
 
 
* '''[GW1998]'''
 
* dimension of symmetric algebra and exterior algebra of V_k
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 3.428em; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; color: rgb(34, 61, 103); font-family: 'malgun gothic', dotum, gulim, sans-serif; font-size: 1.166em; background-image: ; background-color: initial; background-position: 0px 100%;">symmetric power of sl(2) representations</h5>
 
 
 
*  q-binomial type formula<br><math>\prod_{j=0}^{k}(1-tq^{k-2j})^{-1}=\sum_{j=0}^{\infty}t^j\begin{bmatrix} k+j\\ k\end{bmatrix}_{q}</math><br>
 
*  the character of j-th symmetric power of V_k is<br><math>\begin{bmatrix} k+j\\ k\end{bmatrix}_{q}</math><br> where the q-analogue of the natural number is defined as <br><math>[n]_{q}=\frac{q^n-q^{-n}}{q-q^{-1}}</math><br>
 
 
 
 
 
 
 
(proof)
 
 
 
Fix a k throughout the argument.
 
 
 
Let <math>F_j(q)</math> be the character of j-th symmetric power of V_k.
 
 
 
<math>F_j(q)=\sum_{m_0,\cdots,m_k}q^{(k-0)m_0+(k-2)m_1+\cdots+(2-k)m_{k-1}+(0-k)m_k}</math>
 
 
 
where <math>m_0+m_1+\cdots+m_k=j</math>
 
 
 
Now consider the generating function
 
 
 
<math>F(t,q)=\sum_{j=0}^{\infty}F_j(q)t^j</math>
 
 
 
I claim that
 
 
 
<math>F(t,q)=\sum_{j=0}^{\infty}F_j(q)t^j=\prod_{j=0}^{k}(1-tq^{k-2j})^{-1}</math>. 
 
 
 
To prove that see the power series expansion of a factor:
 
 
 
<math>(1-tq^{k-2j})^{-1}=\sum_{m=0}^{\infty}t^mq^{m(k-2j)}</math>. Therefore
 
 
 
<math>\prod_{j=0}^{k}(1-tq^{k-2j})^{-1}=\sum_{m_0,\cdots,m_k}t^{m_0+\cdots+m_k}q^{(k-0)m_0+(k-2)m_1+\cdots+(2-k)m_{k-1}+(0-k)m_k}</math>
 
 
 
Now we can easily check
 
 
 
<math>\prod_{j=0}^{k}(1-tq^{k-2j})^{-1}=\sum_{j=0}^{\infty}t^j\begin{bmatrix} k+j\\ k\end{bmatrix}_{q}</math>■
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 3.428em; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; color: rgb(34, 61, 103); font-family: 'malgun gothic', dotum, gulim, sans-serif; font-size: 1.166em; background-image: ; background-color: initial; background-position: 0px 100%;">exterior algebra of sl(2) representations</h5>
 
 
 
*  q-binomial type formula (Gauss formula)<br><math>\prod_{j=0}^{k}(1+tq^{k-2j})}=\sum_{j=0}^{k+1}\begin{bmatrix} k+1 \\ j\end{bmatrix}_{q}q^{j(j-1)/2}t^j</math><br>
 
*  the character of j-th exterior algebra of V_k is<br><math>\begin{bmatrix} k+1 \\ j\end{bmatrix}_{q}q^{j(j-1)/2}</math><br>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
<h5>Clebsch-Gordan coefficients</h5>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
<h5>Catalan numbers</h5>
 
 
 
# f[n_] := Integrate[(2 Cos[Pi*x])^n*2 (Sin[Pi*x])^2, {x, 0, 1}]<br> Table[Simplify[f[2 k]], {k, 1, 10}]<br> Table[CatalanNumber[n], {n, 1, 10}]
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
<h5>history</h5>
 
 
 
* http://www.google.com/search?hl=en&tbs=tl:1&q=
 
 
 
 
 
 
 
 
 
 
 
<h5>related items</h5>
 
 
 
* [[cyclotomic numbers and Chebyshev polynomials]]
 
* [[Weyl-Kac character formula]]
 
 
* [[Macdonald constant term conjecture]]
 
* [[Macdonald constant term conjecture]]
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* {{수학노트|url=리대수 sl(2,C)의 유한차원 표현론}}
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==Catalan numbers==
  
 
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* http://qchu.wordpress.com/2010/03/07/walks-on-graphs-and-tensor-products/
 
+
* http://mathoverflow.net/questions/17197/how-does-this-relationship-between-the-catalan-numbers-and-su2-generalize
<h5 style="line-height: 3.428em; margin: 0px; color: rgb(34, 61, 103);">encyclopedia</h5>
 
 
 
* [http://pythagoras0.springnote.com/pages/4783755 q-이항정리]
 
* [http://pythagoras0.springnote.com/pages/4682477 체비셰프 다항식]
 
* http://en.wikipedia.org/wiki/
 
* http://www.scholarpedia.org/
 
* Princeton companion to mathematics([[2910610/attachments/2250873|Companion_to_Mathematics.pdf]])
 
 
 
 
 
 
 
 
 
 
 
<h5>books</h5>
 
 
 
* '''[GW1998]'''Representations and invariants of the classical groups<br>
 
** Goodman and Wallach
 
* [[2010년 books and articles]]<br>
 
* http://gigapedia.info/1/
 
* http://gigapedia.info/1/
 
* http://www.amazon.com/s/ref=nb_ss_gw?url=search-alias%3Dstripbooks&field-keywords=
 
 
 
 
 
 
 
 
 
 
 
<h5 style="line-height: 3.428em; margin: 0px; color: rgb(34, 61, 103);">articles</h5>
 
 
 
[[2010년 books and articles|]]
 
 
 
* [http://dx.doi.org/10.1063/1.527759 SL(2,C), SU(2), and Chebyshev polynomials]<br>
 
** Henri Bacry, J. Math. Phys. 28, 2259 (1987)
 
* http://www.ams.org/mathscinet
 
* http://www.zentralblatt-math.org/zmath/en/
 
* http://pythagoras0.springnote.com/
 
* [http://math.berkeley.edu/%7Ereb/papers/index.html http://math.berkeley.edu/~reb/papers/index.html]
 
* http://front.math.ucdavis.edu/search?a=&t=&c=&n=40&s=Listings&q=
 
* http://www.ams.org/mathscinet/search/publications.html?pg4=AUCN&s4=&co4=AND&pg5=TI&s5=&co5=AND&pg6=PC&s6=&co6=AND&pg7=ALLF&co7=AND&Submit=Search&dr=all&yrop=eq&arg3=&yearRangeFirst=&yearRangeSecond=&pg8=ET&s8=All&s7=
 
* http://dx.doi.org/10.1063/1.527759
 
 
 
 
 
 
 
 
 
 
 
<h5>question and answers(Math Overflow)</h5>
 
 
 
* http://mathoverflow.net/search?q=
 
* http://mathoverflow.net/search?q=
 
 
 
 
 
 
 
 
 
 
 
<h5>blogs</h5>
 
 
 
*  구글 블로그 검색<br>
 
** http://blogsearch.google.com/blogsearch?q=
 
** http://blogsearch.google.com/blogsearch?q=
 
 
 
 
 
 
 
 
 
 
 
<h5>experts on the field</h5>
 
  
* http://arxiv.org/
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# f[n_] := Integrate[(2 Cos[Pi*x])^n*2 (Sin[Pi*x])^2, {x, 0, 1}]Table[Simplify[f[2 k]], {k, 1, 10}]Table[CatalanNumber[n], {n, 1, 10}]
  
 
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<h5>links</h5>
 
  
* [http://detexify.kirelabs.org/classify.html Detexify2 - LaTeX symbol classifier]
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[[분류:개인노트]]
* [http://pythagoras0.springnote.com/pages/1947378 수식표 현 안내]
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[[분류:math and physics]]
* [http://www.research.att.com/%7Enjas/sequences/index.html The On-Line Encyclopedia of Integer Sequences]
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[[분류:Lie theory]]
* http://functions.wolfram.com/
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[[분류:migrate]]

2020년 12월 28일 (월) 05:21 기준 최신판