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Spherical Functions Associated With the Three Dimensional Sphere
Classical Analysis and ODEs · Submitted 19 Mar 2012
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim In this paper, we determine all irreducible spherical functions \Phi of any K -type associated to the pair (G,K)=(\SO(4),\SO(3)).
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In this paper, we determine all irreducible spherical functions \Phi of any K -type associated to the pair (G,K)=(\SO(4),\SO(3)). This is accomplished by associating to \Phi a vector valued function H=H(u) of a real variable u, which is analytic at u=0 and whose components are solutions of two coupled systems of ordinary differential equations. By an appropriate conjugation involving Hahn polynomials we uncouple one of the systems. Then this is taken to an uncoupled system of hypergeometric equations, leading to a vector valued solution P=P(u) whose entries are Gegenbauer's polynomials. Afterward, we identify those simultaneous solutions and use the representation theory of \SO(4) to characterize all irreducible spherical functions. The functions P=P(u) corresponding to the irreducible spherical functions of a fixed K-type \pi_\ell are appropriately packaged into a sequence of matrix valued polynomials (P_w)_{w\ge0} of size (\ell+1)\times(\ell+1). Finally we proved that \widetilde P_w={P_0}^{-1}P_w is a sequence of matrix orthogonal polynomials with respect to a weight matrix W. Moreover we showed that W admits a second order symmetric hypergeometric operator \widetilde D and a first order symmetric differential operator \widetilde E.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | In this paper, we determine all irreducible spherical functions \Phi of any K -type associated to the pair (G,K)=(\SO(4),\SO(3)). | contribution 0.83 | 0.97 | 0.85 | asserted 1.00 |
| s1 | This is accomplished by associating to \Phi a vector valued function H=H(u) of a real variable u, which is analytic at u=0 and whose components are solutions of two coupled systems of ordinary differential equations. | method 0.99 | 0.95 | 0.04 | asserted 1.00 |
| s2 | By an appropriate conjugation involving Hahn polynomials we uncouple one of the systems. | method 0.99 | 0.94 | 0.02 | asserted 1.00 |
| s3 | Then this is taken to an uncoupled system of hypergeometric equations, leading to a vector valued solution P=P(u) whose entries are Gegenbauer's polynomials. | method 0.97 | 0.94 | 0.06 | asserted 1.00 |
| s4 | Afterward, we identify those simultaneous solutions and use the representation theory of \SO(4) to characterize all irreducible spherical functions. | method 0.66 | 0.96 | 0.42 | asserted 1.00 |
| s5 | The functions P=P(u) corresponding to the irreducible spherical functions of a fixed K-type \pi_\ell are appropriately packaged into a sequence of matrix valued polynomials (P_w)_{w\ge0} of size (\ell+1)\times(\ell+1). | contribution 0.44 | 0.93 | 0.10 | asserted 1.00 |
| s6 | Finally we proved that \widetilde P_w={P_0}^{-1}P_w is a sequence of matrix orthogonal polynomials with respect to a weight matrix W. | result 0.94 | 0.97 | 0.27 | asserted 1.00 |
| s7 | Moreover we showed that W admits a second order symmetric hypergeometric operator \widetilde D and a first order symmetric differential operator \widetilde E. | result 0.96 | 0.96 | 0.16 | asserted 1.00 |
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Original abstract
In this paper, we determine all irreducible spherical functions \Phi of any K -type associated to the pair (G,K)=(\SO(4),\SO(3)). This is accomplished by associating to \Phi a vector valued function H=H(u) of a real variable u, which is analytic at u=0 and whose components are solutions of two coupled systems of ordinary differential equations. By an appropriate conjugation involving Hahn polynomials we uncouple one of the systems. Then this is taken to an uncoupled system of hypergeometric equations, leading to a vector valued solution P=P(u) whose entries are Gegenbauer's polynomials. Afterward, we identify those simultaneous solutions and use the representation theory of \SO(4) to characterize all irreducible spherical functions. The functions P=P(u) corresponding to the irreducible spherical functions of a fixed K-type \pi_\ell are appropriately packaged into a sequence of matrix valued polynomials (P_w)_{w\ge0} of size (\ell+1)\times(\ell+1). Finally we proved that \widetilde P_w={P_0}^{-1}P_w is a sequence of matrix orthogonal polynomials with respect to a weight matrix W. Moreover we showed that W admits a second order symmetric hypergeometric operator \widetilde D and a first order symmetric differential operator \widetilde E.
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2 arXiv papers cite this in 2 sentences
Papers citing it
Cites it as support 1 paper
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For $m=3$ this follows from [ref] or [ref] .
Matrix Valued Classical Pairs Related to Compact Gelfand Pairs of Rank One · Differential properties · 0.96
Cites it as background 1 paper
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The work by Zurrián mentioned in the Introduction is now available in [ref] .
Matrix-valued orthogonal polynomials related to (SU(2)\times SU(2),diag), II · Acknowledgement. · 0.85
What it cites · 2 sentences without a confident label
Contests 1 paper
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Unfortunately the expression of $Ẽ$ in Theorem 3.1 of [ref] is wrong.
Matrix Valued Orthogonal Polynomials related to (SU(2) x SU(2),diag) · The Inner Product · contest 0.88
Compares with 1 paper
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The results of this paper and those in [ref] are in agreement,
Matrix Valued Orthogonal Polynomials related to (SU(2) x SU(2),diag) · Introduction · 0.99
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