A two-variable extension of Bannai-Ito polynomials is presented. They are obtained via q → −1 limits of the bivariate q-Racah and Askey-Wilson orthogonal polynomials introduced by Gasper and Rahman. Their orthogonality relation is obtained. These new polynomials are also shown to be multispectral. Two Dunkl shift operators are seen to be diagonalized by the bivariate Bannai-Ito polynomials and 3- and 9-term recurrence relations are provided.

1.
E.
Bannai
and
T.
Ito
,
Algebraic Combinatorics
(
Benjamin/Cummings Menlo Park
,
1984
).
2.
S.
Tsujimoto
,
L.
Vinet
, and
A.
Zhedanov
, “
Dunkl shift operators and Bannai–Ito polynomials
,”
Adv. Math.
229
(
4
),
2123
2158
(
2012
).
3.
V.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
The non-symmetric Wilson polynomials are the Bannai–Ito polynomials
,”
Proc. Am. Math. Soc.
144
(
12
),
5217
5226
(
2016
).
4.
V.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
The Bannai-Ito polynomials as Racah coefficients of the sl−1(2) algebra
,”
Proc. Am. Math. Soc.
142
(
5
),
1545
1560
(
2014
).
5.
V. X.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
A Laplace-Dunkl equation on S2 and the Bannai–Ito algebra
,”
Commun. Math. Phys.
336
(
1
),
243
259
(
2015
).
6.
H.
De Bie
,
V. X.
Genest
, and
L.
Vinet
, “
A Dirac–Dunkl equation on S2 and the Bannai–Ito algebra
,”
Commun. Math. Phys.
344
(
2
),
447
464
(
2016
).
7.
V. X.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
The Bannai–Ito algebra and a superintegrable system with reflections on the two-sphere
,”
J. Phys. A: Math. Theor.
47
(
20
),
205202
(
2014
).
8.
L.
Vinet
and
A.
Zhedanov
, “
A missing family of classical orthogonal polynomials
,”
J. Phys. A: Math. Theor.
44
(
8
),
085201
(
2011
).
9.
L.
Vinet
and
A.
Zhedanov
, “
A limit q = −1 for the big q-Jacobi polynomials
,”
Trans. Am. Math. Soc.
364
(
10
),
5491
5507
(
2012
).
10.
L.
Vinet
,
A.
Zhedanov
 et al, “
A Bochner theorem for Dunkl polynomials
,”
Symmetry, Integrability Geom.: Methods Appl.
7
,
020
(
2011
).
11.
S.
Tsujimoto
,
L.
Vinet
, and
A.
Zhedanov
, “
Dual -1 Hahn polynomials: Classical polynomials beyond the Leonard duality
,”
Proc. Am. Math. Soc.
141
(
3
),
959
970
(
2013
).
12.
V. X.
Genest
,
L.
Vinet
,
A.
Zhedanov
 et al, “
Bispectrality of the complementary Bannai-Ito polynomials
,”
Symmetry, Integrability Geom.: Methods Appl.
9
,
018
(
2013
).
13.
V. X.
Genest
,
L.
Vinet
, and
A. S.
Zhedanov
, “
A continuous limit of the complementary Bannai–Ito polynomials: Chihara polynomials
,”
Symmetry, Integrability Geom.: Methods Appl.
10
,
038
(
2014
).
14.
C. F.
Dunkl
and
Y.
Xu
,
Orthogonal Polynomials of Several Variables
(
Cambridge University Press
,
2014
), Vol. 155.
15.
L.
Fernández
,
F.
Marcellán
,
T. E.
Pérez
, and
M. A.
Pinar
, “
Recent trends on two variable orthogonal polynomials
,” in
Differential Algebra, Complex Analysis and Orthogonal Polynomials
(
The American Mathematical Society Providence
,
RI
,
2010
), Vol. 509, pp.
59
86
.
16.
I. G.
Macdonald
 et al,
Affine Hecke Algebras and Orthogonal Polynomials
(
Cambridge University Press
,
2003
), Vol. 157.
17.
M.
Tratnik
, “
Some multivariable orthogonal polynomials of the askey tableau-discrete families
,”
J. Math. Phys.
32
(
9
),
2337
2342
(
1991
).
18.
M.
Tratnik
, “
Some multivariable orthogonal polynomials of the Askey tableau—Continuous families
,”
J. Math. Phys.
32
(
8
),
2065
2073
(
1991
).
19.
J. S.
Geronimo
and
P.
Iliev
, “
Bispectrality of multivariable Racah–Wilson polynomials
,”
Constr. Approximation
31
(
3
),
417
457
(
2010
).
20.
P.
Iliev
, “
Bispectral commuting difference operators for multivariable Askey-Wilson polynomials
,”
Trans. Am. Math. Soc.
363
(
3
),
1577
1598
(
2011
).
21.
G.
Gasper
and
M.
Rahman
, “
Some systems of multivariable orthogonal q-Racah polynomials
,”
Ramanujan J.
13
(
1-3
),
389
405
(
2007
).
22.
G.
Gasper
and
M.
Rahman
, “
Some systems of multivariable orthogonal Askey-Wilson polynomials
,” in
Theory and Applications of Special Functions
(
Springer
,
2005
), pp.
209
219
.
23.
T. S.
Chihara
,
An Introduction to Orthogonal Polynomials
(
Gordon and Breach
,
1978
).
24.
J.-M.
Lemay
,
L.
Vinet
, and
A.
Zhedanov
, “
The para-Racah polynomials
,”
J. Math. Anal. Appl.
438
(
2
),
565
577
(
2016
).
25.
J.-M.
Lemay
,
L.
Vinet
, and
A.
Zhedanov
, “
A q-generalization of the para-Racah polynomials
,”
J. Math. Anal. Appl.
462
(
1
),
323
336
(
2018
).
26.
R.
Koekoek
,
P. A.
Lesky
, and
R. F.
Swarttouw
,
Hypergeometric Orthogonal Polynomials and Their Q-Analogues
(
Springer Science & Business Media
,
2010
).
27.
H.
De Bie
,
V. X.
Genest
, and
L.
Vinet
, “
The Z2n Dirac–Dunkl operator and a higher rank Bannai-Ito algebra
,”
Adv. Math.
303
,
390
414
(
2016
).
28.
H.
De Bie
,
V. X.
Genest
,
J.-M.
Lemay
, and
L.
Vinet
, “
A superintegrable model with reflections on S3 and the rank two Bannai-Ito algebra
,”
Acta Polytech.
56
,
166
172
(
2016
).
29.
H.
De Bie
,
V. X.
Genest
,
J.-M.
Lemay
, and
L.
Vinet
, “
A superintegrable model with reflections on Sn−1 and the higher rank Bannai-Ito algebra
,”
J. Phys. A: Math. Theor.
50
(
19
),
195202
(
2017
).
30.

It might be possible to absorb this singularity with some fine-tuning of the parameters as has been done for the Racah and q-Racah polynomials,24,25 but this has not been explored yet and goes beyond the scope of this paper.

You do not currently have access to this content.