scholarly journals Combinatorial Proofs of Addition Formulas

10.37236/4793 ◽  
2016 ◽  
Vol 23 (1) ◽  
Author(s):  
Xiang-Ke Chang ◽  
Xing-Biao Hu ◽  
Hongchuan Lei ◽  
Yeong-Nan Yeh
Keyword(s):  
Hankel Matrix ◽  
Direct Consequence ◽  
Combinatorial Proof ◽  
Addition Formula ◽  
Polynomial Sequence ◽  
Schröder Paths ◽  
Motzkin Paths ◽  
Addition Formulas

In this paper we give a combinatorial proof of an addition formula for weighted partial Motzkin paths. The addition formula allows us to determine the $LDU$ decomposition of a Hankel matrix of the polynomial sequence defined by weighted partial Motzkin paths. As a direct consequence, we get the determinant of the Hankel matrix of certain combinatorial sequences. In addition, we obtain an addition formula for weighted large Schröder paths.

scholarly journals On a dual relation for addition formulas of additive groups II

1985 ◽  
Vol 97 ◽  
pp. 95-135 ◽  
Author(s):  
Toshihiro Watanabe
Keyword(s):  
Addition Formula ◽  
Polynomial Sequence ◽  
Several Variables ◽  
Classical Polynomials ◽  
Dual Relation ◽  
Addition Formulas

This paper is a continuation of our previous memoir [28], hereafter referred to as I, and constitutes the second chapter of this series. As stated in I, our aim in this series is to examine properties of a polynomial sequence with several variables satisfying an addition formula by means of the down-ladder, and to give a generalization of so called classical polynomials.

scholarly journals New Tribonacci recurrence relations and addition formulas

2020 ◽  
Vol 26 (4) ◽  
pp. 164-172
Author(s):  
Kunle Adegoke ◽  
◽  
Adenike Olatinwo ◽  
Winning Oyekanmi ◽  
◽  
...  
Keyword(s):  
Recurrence Relation ◽  
Recurrence Relations ◽  
Simple Relation ◽  
Addition Formula ◽  
Lucas Numbers ◽  
Tribonacci Numbers ◽  
Three Term Recurrence Relation ◽  
Special Case ◽  
Addition Formulas

Only one three-term recurrence relation, namely, W_{r}=2W_{r-1}-W_{r-4}, is known for the generalized Tribonacci numbers, W_r, r\in Z, defined by W_{r}=W_{r-1}+W_{r-2}+W_{r-3} and W_{-r}=W_{-r+3}-W_{-r+2}-W_{-r+1}, where W_0, W_1 and W_2 are given, arbitrary integers, not all zero. Also, only one four-term addition formula is known for these numbers, which is W_{r + s} = T_{s - 1} W_{r - 1} + (T_{s - 1} + T_{s-2} )W_r + T_s W_{r + 1}, where ({T_r})_{r\in Z} is the Tribonacci sequence, a special case of the generalized Tribonacci sequence, with W_0 = T_0 = 0 and W_1 = W_2 = T_1 = T_2 = 1. In this paper we discover three new three-term recurrence relations and two identities from which a plethora of new addition formulas for the generalized Tribonacci numbers may be discovered. We obtain a simple relation connecting the Tribonacci numbers and the Tribonacci–Lucas numbers. Finally, we derive quadratic and cubic recurrence relations for the generalized Tribonacci numbers.

scholarly journals Vertically Constrained Motzkin-Like Paths Inspired by Bobbin Lace

10.37236/7799 ◽  
2019 ◽  
Vol 26 (2) ◽  
Author(s):  
Veronika Irvine ◽  
Stephen Melczer ◽  
Frank Ruskey
Keyword(s):  
Mathematical Model ◽  
Generating Functions ◽  
Finite Lattice ◽  
Lattice Paths ◽  
Change Direction ◽  
Quarter Plane ◽  
Directed Paths ◽  
Schröder Paths ◽  
Motzkin Paths

Inspired by a new mathematical model for bobbin lace, this paper considers finite lattice paths formed from the set of step vectors $\mathfrak{A}=$$\{\rightarrow,$ $\nearrow,$ $\searrow,$ $\uparrow,$ $\downarrow\}$ with the restriction that vertical steps $(\uparrow, \downarrow)$ cannot be consecutive. The set $\mathfrak{A}$ is the union of the well known Motzkin step vectors $\mathfrak{M}=$$\{\rightarrow,$ $\nearrow,$ $\searrow\}$ with the vertical steps $\{\uparrow, \downarrow\}$. An explicit bijection $\phi$ between the exhaustive set of vertically constrained paths formed from $\mathfrak{A}$ and a bisection of the paths generated by $\mathfrak{M}S$ is presented. In a similar manner, paths with the step vectors $\mathfrak{B}=$$\{\nearrow,$ $\searrow,$ $\uparrow,$ $\downarrow\}$, the union of Dyck step vectors and constrained vertical steps, are examined.  We show, using the same $\phi$ mapping, that there is a bijection between vertically constrained $\mathfrak{B}$ paths and the subset of Motzkin paths avoiding horizontal steps at even indices.  Generating functions are derived to enumerate these vertically constrained, partially directed paths when restricted to the half and quarter-plane.  Finally, we extend Schröder and Delannoy step sets in a similar manner and find a bijection between these paths and a subset of Schröder paths that are smooth (do not change direction) at a regular horizontal interval.

scholarly journals Touchard-Riordan formulas, T-fractions, and Jacobi's triple product identity

2011 ◽  
Vol DMTCS Proceedings vol. AO,... (Proceedings) ◽  
Author(s):  
Matthieu Josuat-Vergès ◽  
Jang-Soo Kim
Keyword(s):  
Functional Equation ◽  
Triple Product ◽  
Combinatorial Proof ◽  
Jacobi’S Triple Product Identity ◽  
Product Identity ◽  
Nous Montrons ◽  
Schröder Paths ◽  
International Audience ◽  
Finite Sum ◽  
Jacobi's Triple Product Identity

International audience We give a combinatorial proof of a Touchard-Riordan-like formula discovered by the first author. As a consequence we find a connection between his formula and Jacobi's triple product identity. We then give a combinatorial analog of Jacobi's triple product identity by showing that a finite sum can be interpreted as a generating function of weighted Schröder paths, so that the triple product identity is recovered by taking the limit. This can be stated in terms of some continued fractions called T-fractions, whose important property is the fact that they satisfy some functional equation. We show that this result permits to explain and generalize some Touchard-Riordan-like formulas appearing in enumerative problems. Nous donnons une preuve combinatoire d'une formule à la Touchard-Riordan due au premier auteur. En conséquence, nous faisons appara\^ıtre un lien entre cette formule et l'identité du produit triple de Jacobi. Nous donnons un analogue combinatoire à l'identité du produit triple en montrant qu'une somme finie peut être interprétée comme fonction génératrice de chemins de Schröder pondérés, de sorte que l'identité du produit triple s'obtient en passant à la limite. Ceci peut être énoncé en termes de fractions continues appelées T-fractions, dont la propriété importante est le fait qu'elle satisfont certaines équations fonctionnelles. Nous montrons que ce résultat permet d'expliquer et généraliser certaines formules à la Touchard-Riordan apparaissant dans des problèmes d'énumération.

A Relation Between Schröder Paths and Motzkin Paths

2020 ◽  
Vol 36 (5) ◽  
pp. 1489-1502
Author(s):  
Lin Yang ◽  
Sheng-Liang Yang
Keyword(s):  
Schröder Paths ◽  
Motzkin Paths

scholarly journals Combinatorics of the Free Baxter Algebra

10.37236/1043 ◽  
2006 ◽  
Vol 13 (1) ◽  
Author(s):  
Marcelo Aguiar ◽  
Walter Moreira
Keyword(s):  
Explicit Description ◽  
Combinatorial Objects ◽  
Linear Basis ◽  
Alternative Description ◽  
Generating Series ◽  
Schröder Paths ◽  
Motzkin Paths

We study the free (associative, non-commutative) Baxter algebra on one generator. The first explicit description of this object is due to Ebrahimi-Fard and Guo. We provide an alternative description in terms of a certain class of trees, which form a linear basis for this algebra. We use this to treat other related cases, particularly that in which the Baxter map is required to be quasi-idempotent, in a unified manner. Each case corresponds to a different class of trees. Our main focus is on the underlying combinatorics. In several cases, we provide bijections between our various classes of trees and more familiar combinatorial objects including certain Schröder paths and Motzkin paths. We calculate the dimensions of the homogeneous components of these algebras (with respect to a bidegree related to the number of nodes and the number of angles in the trees) and the corresponding generating series. An important feature is that the combinatorics is captured by the idempotent case; the others are obtained from this case by various binomial transforms. We also relate free Baxter algebras to Loday's dendriform trialgebras and dialgebras. We show that the free dendriform trialgebra (respectively, dialgebra) on one generator embeds in the free Baxter algebra with a quasi-idempotent map (respectively, with a quasi-idempotent map and an idempotent generator). This refines results of Ebrahimi-Fard and Guo.

scholarly journals A Combinatorial Derivation with Schröder Paths of a Determinant Representation of Laurent Biorthogonal Polynomials

10.37236/800 ◽  
2008 ◽  
Vol 15 (1) ◽  
Author(s):  
Shuhei Kamioka
Keyword(s):  
Recurrence Equation ◽  
Combinatorial Proof ◽  
Toeplitz Determinants ◽  
Determinant Representation ◽  
Combinatorial Derivation ◽  
Schröder Paths ◽  
Biorthogonal Polynomials ◽  
Weighted Plane

A combinatorial proof in terms of Schröder paths and other weighted plane paths is given for a determinant representation of Laurent biorthogonal polynomials (LBPs) and that of coefficients of their three-term recurrence equation. In this process, it is clarified that Toeplitz determinants of the moments of LBPs and their minors can be evaluated by enumerating certain kinds of configurations of Schröder paths in a plane.

scholarly journals Computation of Al-Salam Carlitz and Askey-Wilson Moments using Motzkin Paths

10.37236/9780 ◽  
2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Gaspard Ohlmann
Keyword(s):  
Combinatorial Proof ◽  
Combinatorial Approach ◽  
Motzkin Path ◽  
Wilson Polynomials ◽  
Motzkin Paths

In this paper we study the moments of polynomials from the Askey scheme, and we focus on Askey-Wilson polynomials. More precisely, we give a combinatorial proof for the case where $d=0$. Their values have already been computed by Kim and Stanton in 2015, however, the proof is not completely combinatorial, which means that an explicit bijection has not been exhibited yet. In this work, we use a new combinatorial approach for the simpler case of Al-Salam-Carlitz, using a sign reversing involution that directly operates on Motzkin path. We then generalize this method to Askey-Wilson polynomials with $d=0$ only, providing the first fully combinatorial proof for that case.

scholarly journals Dual addition formulas: the case of continuous q-ultraspherical and q-Hermite polynomials

2021 ◽  
Author(s):  
Tom H. Koornwinder
Keyword(s):  
Hermite Polynomials ◽  
Constant Term ◽  
The Self ◽  
Limit Case ◽  
Addition Formula ◽  
Ultraspherical Polynomials ◽  
Self Duality ◽  
Racah Polynomials ◽  
Linearization Formula ◽  
Addition Formulas

AbstractWe settle the dual addition formula for continuous q-ultraspherical polynomials as an expansion in terms of special q-Racah polynomials for which the constant term is given by the linearization formula for the continuous q-ultraspherical polynomials. In a second proof we derive the dual addition formula from the Rahman–Verma addition formula for these polynomials by using the self-duality of the polynomials. We also consider the limit case of continuous q-Hermite polynomials.

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