Askey-Wilson relations and Leonard pairs
نویسنده
چکیده
It is known that if (A,A∗) is a Leonard pair, then the linear transformations A, A∗ satisfy the Askey-Wilson relations A 2 A ∗ − βAA ∗ A + A∗A2 − γ (AA∗+A∗A) − ̺A∗ = γ∗A2 + ωA + η I, A ∗2 A− βA ∗ AA ∗+ AA∗2− γ∗(A∗A+AA∗) − ̺∗A = γA∗2+ ωA∗+ η∗I, for some scalars β, γ, γ∗, ̺, ̺∗, ω, η, η∗. The problem of this paper is the following: given a pair of Askey-Wilson relations as above, how many Leonard pairs are there that satisfy those relations? It turns out that the answer is 5 in general. We give the generic number of Leonard pairs for each Askey-Wilson type of Askey-Wilson relations. AMS 2000 MSC Classification: 05E35, 33D45, 33C45.
منابع مشابه
Normalized Leonard pairs and Askey-Wilson relations
Let V denote a vector space with finite positive dimension, and let (A,A∗) denote a Leonard pair on V . As is known, the linear transformations A, A∗ satisfy the Askey-Wilson relations A 2 A ∗ − βAA ∗ A+A∗A2 − γ (AA∗+A∗A)− ̺A∗ = γ∗A2 + ωA+ η I, A ∗2 A− βA ∗ AA ∗+ AA∗2− γ∗(A∗A+AA∗)− ̺∗A = γA∗2+ ωA∗+ η∗I, for some scalars β, γ, γ∗, ̺, ̺∗, ω, η, η∗. The scalar sequence is unique if the dimension of V ...
متن کاملLeonard pairs and the Askey- Wilson relations
Let K denote a field and let V denote a vector space over K with finite positive dimension. We consider an ordered pair of linear transformations A : V → V and A : V → V which satisfy the following two properties: (i) There exists a basis for V with respect to which the matrix representing A is irreducible tridiagonal and the matrix representing A is diagonal. (ii) There exists a basis for V wi...
متن کاملNonsymmetric Askey-Wilson polynomials and Q-polynomial distance-regular graphs
In his famous theorem (1982), Douglas Leonard characterized the q-Racah polynomials and their relatives in the Askey scheme from the duality property of Q-polynomial distance-regular graphs. In this paper we consider a nonsymmetric (or Laurent) version of the q-Racah polynomials in the above situation. Let Γ denote a Q-polynomial distance-regular graph that contains a Delsarte clique C. Assume ...
متن کاملOn Some Limit Cases of Askey-wilson Polynomials
We show that limit transitions from Askey-Wilson polynomials to q-Racah, little and big q-Jacobi polynomials can be made rigorous on the level of their orthogonality measures in a suitable weak sense. This allows us to derive the orthogonality relations and norm evaluations for the q-Racah polynomials, little and big q-Jacobi polynomials by taking limits in the orthogonality relations and norm ...
متن کاملOrthogonal basic hypergeometric Laurent polynomials
The Askey-Wilson polynomials are orthogonal polynomials in x = cos θ, which are given as a terminating 4φ3 basic hypergeometric series. The non-symmetric AskeyWilson polynomials are Laurent polynomials in z = eiθ, which are given as a sum of two terminating 4φ3’s. They satisfy a biorthogonality relation. In this paper new orthogonality relations for single 4φ3’s which are Laurent polynomials in...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Discrete Mathematics
دوره 308 شماره
صفحات -
تاریخ انتشار 2008