New identities for some symmetric polynomials, and a higher order analogue of the Fibonacci and Lucas numbers
Genki Shibukawa

TL;DR
This paper introduces new identities for symmetric polynomials and applies them to derive formulas for higher order analogues of Fibonacci and Lucas numbers, expanding understanding of these classical sequences.
Contribution
It presents novel identities for symmetric polynomials and uses them to develop higher order Fibonacci and Lucas number formulas, a new approach in this area.
Findings
New identities for symmetric polynomials
Formulas for higher order Fibonacci numbers
Formulas for higher order Lucas numbers
Abstract
We give new identities for some symmetric polynomials. As applications of these identities, we obtain some formulas for a higher order analogue of Fibonacci and Lucas numbers.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 2 | 1 | 1 | 2 | 3 | 5 | 8 | 13 | 21 | 34 | 55 | 89 | 144 |
| 3 | 1 | 1 | 3 | 4 | 9 | 14 | 28 | 47 | 89 | 155 | 286 | 507 |
| 4 | 1 | 1 | 4 | 5 | 14 | 20 | 48 | 75 | 165 | 274 | 571 | 988 |
| 5 | 1 | 1 | 5 | 6 | 20 | 27 | 75 | 110 | 275 | 429 | 1001 | 1637 |
| 6 | 1 | 1 | 6 | 7 | 27 | 35 | 110 | 154 | 429 | 637 | 1638 | 2548 |
| 7 | 1 | 1 | 7 | 8 | 35 | 44 | 154 | 208 | 637 | 910 | 2548 | 3808 |
| 8 | 1 | 1 | 8 | 9 | 44 | 54 | 208 | 273 | 910 | 1260 | 3808 | 5508 |
| 9 | 1 | 1 | 9 | 10 | 54 | 65 | 273 | 350 | 1260 | 1700 | 5508 | 7752 |
| 10 | 1 | 1 | 10 | 11 | 65 | 77 | 350 | 440 | 1700 | 2244 | 7752 | 10659 |
| 11 | 1 | 1 | 11 | 12 | 77 | 90 | 440 | 544 | 2244 | 2907 | 10659 | 14364 |
| 12 | 1 | 1 | 12 | 13 | 90 | 104 | 544 | 663 | 2907 | 3705 | 14364 | 19019 |
| 13 | 1 | 1 | 13 | 14 | 104 | 119 | 663 | 798 | 3705 | 4655 | 19019 | 24794 |
| 14 | 1 | 1 | 14 | 15 | 119 | 135 | 798 | 950 | 4655 | 5775 | 24794 | 31878 |
| 15 | 1 | 1 | 15 | 16 | 135 | 152 | 950 | 1120 | 5775 | 7084 | 31878 | 40480 |
| 16 | 1 | 1 | 16 | 17 | 152 | 170 | 1120 | 1309 | 7084 | 8602 | 40480 | 50830 |
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Taxonomy
TopicsAdvanced Mathematical Theories and Applications · Advanced Mathematical Identities · Advanced Combinatorial Mathematics
New identities for some symmetric polynomials, and a higher order analogue of the Fibonacci and Lucas numbers
Genki Shibukawa
( MSC classes : 05E05, 11B39, 33C05)
Abstract
We give new identities for some symmetric polynomials. As applications of these identities, we obtain some formulas for a higher order analogue of Fibonacci and Lucas numbers.
1 Introduction
Throughout the paper, we denote the set of non-negative integers by , the field of real numbers by , the field of complex numbers by and . Let be independent variables and . For each non-negative integer , the th elementary symmetric polynomial , complete homogeneous polynomials and power symmetric polynomial are defined by
[TABLE]
respectively. For , we put
[TABLE]
Our main results are new identities for these three types of symmetric polynomials , which are relationships between and . More precisely, we determine the following expansion coefficients and ,
[TABLE]
In this article we call (1.4) (resp. (1.5)) the first kind formulas (resp. the second kind formulas).
Theorem 1** (The first kind formulas).**
*For any non-negative integer , we have the following identities.
(1)*
[TABLE]
where
[TABLE]
*and is the greatest integer not exceeding .
(2)*
[TABLE]
(3)**
[TABLE]
Theorem 2** (The second kind formulas).**
(1)* For , we have*
[TABLE]
(2)* For any non-negative integer ,*
[TABLE]
(3)* For any positive integer ,*
[TABLE]
The proofs of (1.6) and (1.7) are more difficult than (1.9) and (1.10). In particular we need a hypergeometric identity (2.20) to derive the explicit formulas of or . The second kind formulas and (1.8) which are proved immediately by the binomial formula and generating functions may be well known. However we have not found appropriate references about these formulas and their interesting applications which are to propose some new formulas of Fibonacci and Lucas numbers etc. In particular, we apply Theorem 1 and Theorem 2 to some special values of and ;
[TABLE]
where
[TABLE]
Since the case of is trivial sequences
[TABLE]
and the case of is the classical Fibonacci numbers and Lucas numbers
[TABLE]
the sequences and are regarded as a higher order analogue of the classical Fibonacci and Lucas numbers. From Theorem 1, Theorem 2 and some fundamental results for symmetric functions, we propose the following fundamental formulas for and .
Theorem 3** (Explicit formulas of and ).**
[TABLE]
where
[TABLE]
Theorem 4** (Inversion of the explicit formulas).**
[TABLE]
Theorem 5** (Initial values and recurrence formulas).**
Initial values of and are given by
[TABLE]
The sequences and satisfy the following same recursion:
[TABLE]
The content of this article is as follows. In Section 2, we refer some basic formulas for symmetric polynomials and the Gauss hypergeometric function from [AAR] and [M]. Section 3 is the main part of this article. In this section, we prove Theorem 1 and Theorem 2, and give their principal specialization. In Section 4, we evaluate , and by the definitions and generating functions. By substituting these evaluations into Theorem 1 and Theorem 2, we propose Theorem 3, Theorem 4 and Theorem 5. Further, we consider some specializations of our main results and drive some interesting binomial sum formulas, including new formulas for the Fibonacci and Lucas numbers (see Corollary 18 and Corollary 19). In Appendix, we mention some congruence properties and other formulas (generating functions, determinant formulas, some relations) for and that are proven independently of Theorem 1 and Theorem 2.
2 Preliminaries
2.1 Symmetric polynomials
Refer to Macdonald [M] for the details in this subsection. We fix a positive integer , and denote the partition set of length by
[TABLE]
and the symmetric group of degree by . For some special partitions, we use the following notations
[TABLE]
The symmetric group acts on by
[TABLE]
For any partition , we define Schur polynomial and monomial symmetry polynomial by
[TABLE]
where is the usual determinant and
[TABLE]
We remark that Schur polynomial extends to Schur function for by (2.1).
It is well known that
[TABLE]
which is Schur or monomial with one column are , and monomial with one row is , and Schur with one row is ([M] Chapter I Section 3 (3.9)). From (2.5), we extend the complete homogeneous polynomials to : namely
[TABLE]
By this extension (2.6) and the definition of Schur function, for any we have
[TABLE]
We list up some required formulas for symmetric polynomials in [M].
Lemma 6**.**
(1)* Generating functions*
[TABLE]
(2)* -binomial formula*
[TABLE]
where denotes the -binomial coefficient
[TABLE]
(3)* Wronski relation and Newton’s formula *
[TABLE]
Actually, (2.8) is [M] p19 (2.2) and (2.9) is [M] p21 (2.5) exactly. For (2.11) and (2.12), see [M] p26 Examples 3. Similarly, (2.13) and (2.14) are [M] p21 (2.6*′) and p23 (2.11′*) respectively.
2.2 The Gauss hypergeometric function
Let be complex numbers such that is not non-negative integers, and be the raising factorial defined by
[TABLE]
We recall Gauss hypergeometric function
[TABLE]
and for any complex numbers and we put
[TABLE]
Since
[TABLE]
the function is analytically continued to by analytic continuation of .
Lemma 7**.**
(1)* Another expression*
[TABLE]
(2)* Closed form*
[TABLE]
(3)* Index law*
[TABLE]
(4)* Quadratic formula*
[TABLE]
Proof.
(1) By the definition of and , we have
[TABLE]
(2) We remark a hypergeometric transformation [AAR] (3.1.10)
[TABLE]
Thus,
[TABLE]
The formulas (2.18) and (2.19) follow from (2.17) immediately. ∎
The following Lemma is a corollary of Lemma 7 and the key step in the proof of Theorem 1.
Lemma 8**.**
If
[TABLE]
then
[TABLE]
and for any non-negative integer
[TABLE]
Proof.
By quadratic formula,
[TABLE]
Thus, we have
[TABLE]
Here the second and third equalities follow from (2.18) and (2.16) respectively. ∎
Remark 9**.**
We mention some properties of . For non-negative integers and , we make the table of .
This table is determined exactly by initial conditions
[TABLE]
and a recursion formula
[TABLE]
The sequence is a kind of Clebsch-Gordan coefficients for the Lie algebra . In fact, from the above initial conditions and recursion of , we have
[TABLE]
that is the classical Clebsch-Gordan rule for exactly.
Further is also a typical example of Kostka numbers (see [S] Chapter 2 Section 2.11 and Chapter 4 Section 4.9). We remark Young’s rule
[TABLE]
and
[TABLE]
By putting , in (2.22), we have
[TABLE]
Finally, by comparing (2.21) and (2.23), we have
[TABLE]
3 Proofs of Theorem 1 and Theorem 2
From (2.8), (2.9) and simple calculation
[TABLE]
we obtain the following key lemma.
Lemma 10**.**
If
[TABLE]
*then *
[TABLE]
By Lemma 10 and the definition of the power symmetric polynomials, we prove Theorem 1 and Theorem 2.
Proof of Theorem 1 (1) By (3.1),
[TABLE]
where
[TABLE]
Hence, from (2.20) we have
[TABLE]
By comparing coefficients of (3.3) and (3.4), we obtain the conclusion.
(2) Similarly, from (3.2)
[TABLE]
and (2.20) we have
[TABLE]
The formula (1.7) follows from (3.5) and (3.6).
(3) We prove this formula without generating function and other Lemmas. In fact, by applying the usual binomial formula we have
[TABLE]
∎
Proof of Theorem 2 (1) From (3.1) and binomial theorem, we have
[TABLE]
(2) Similarly, we have
[TABLE]
(3) It is enough to show that the case of which is
[TABLE]
From (3.1) and simple calculus,
[TABLE]
If , and , then
[TABLE]
∎
Finally we consider the principal specialization of Theorem 1 and Theorem 2, which means substituting
[TABLE]
for . In this special case, we evaluate , and explicitly.
Proposition 11**.**
*For any non-negative integer , we have the following identities.
(1)*
[TABLE]
(2)**
[TABLE]
(3)**
[TABLE]
Proof.
(1) From generating function of elementary symmetric polynomials (2.8),
[TABLE]
By -binomial formula (2.11), we have
[TABLE]
(2) Similarly, we have
[TABLE]
(3) By the definition of power sum and geometric series, we have
[TABLE]
We remark this formula holds on the limit . ∎
Corollary 12**.**
(1)* For any non-negative integer ,*
[TABLE]
For ,
[TABLE]
(2)* For any non-negative integers and , we have*
[TABLE]
(3)* For any non-negative integer ,*
[TABLE]
For any positive integer ,
[TABLE]
4 Applications to and
In this section we investigate more specializations of Theorem 1 and Theorem 2, and prove Theorem 3, Theorem 4 and Theorem 5. To apply Theorem 1 and Theorem 2 to and , we evaluate , , and .
Proposition 13**.**
(1)* For , we have*
[TABLE]
(2)* For any non-negative integer ,*
[TABLE]
(3)* For any non-negative integer ,*
[TABLE]
where
[TABLE]
Proof.
(1) From (2.8), we have
[TABLE]
(2) From (2.9), we have
[TABLE]
(3) By the definition of ,
[TABLE]
∎
Proof of Theorem 3 and Theorem 4 From Theorem 1 (2) and (3) and Proposition 1 (2) and (3), we derive explicit formulas of and . Similarly, Theorem 4 follows from Theorem 1 (2) and (3) and Proposition 1 (2) and (3). ∎
By specialization of Theorem 3 (2) and (3), we obtain the initial values of and .
Corollary 14**.**
(1)* If , then we have*
[TABLE]
(2)* If , then we have*
[TABLE]
If , then we have
[TABLE]
To prove Theorem 5, we need to evaluate , which can be computed from (1.6) and (4.1).
Proposition 15**.**
For , we have
[TABLE]
Remark 16**.**
(1) For (4.7), we give another proof without using (1.6). Let . First, we remark
[TABLE]
On the other hand, if , then
[TABLE]
Hence we obtain the conclusion (4.7).
(2) The formula (4.7) is obtained by substituting (4.1) into (1.6). Similarly, by substituting (4.1) for (1.9), for we obtain
[TABLE]
Proof of Theorem 5 From the Wronski relations, Newton’s formulas and (4.7), for any non-negative integer we have
[TABLE]
Then and satisfy the recursion (1.20).
The initial values of are determined by the vanishing property (2.7)
[TABLE]
and . The initial values of follows from Corollary 14 (2).∎
Example 17**.**
[TABLE]
(Fibonacci numbers and Lucas numbers)
[TABLE]
(OEIS A006053 and OEIS A096975)
[TABLE]
(OEIS A188021 and OEIS A094649)
[TABLE]
(OEIS A231181 and OEIS A189234)
[TABLE]
[TABLE]
Finally, we mention some interesting examples of our results, including the seemingly new formulas for the Fibonacci and Lucas numbers.
Corollary 18**.**
For any non-negative integers and , we have
[TABLE]
and
[TABLE]
The formula (LABEL:eq:Andrews_Fibonacci_formula) was given by Andrews [A].
Corollary 19**.**
For any non-negative integer , we have
[TABLE]
For any positive integer , we have
[TABLE]
Appendix A Some congruence relations for and
All of the results so far have been obtained as specializations of Theorem 1 and Theorem 2, but in this section, we mention some properties for and that can be obtained independently of Theorem 1 and Theorem 2.
Theorem 20**.**
Let be a prime number. If is a odd prime number such that , then
[TABLE]
In particular, for any non-negative integer we have
[TABLE]
Proof.
Let be a finite field order and be a primitive -th root of unity. Since the both side of (A.1) and (A.2) are integers, it is enough to show that the equalities in . For any integer a simple calculation shows that
[TABLE]
Hence by the definition of we obtain
[TABLE]
To prove (A.1), we need the discriminant of [L] Theorem 3.8
[TABLE]
From this evaluation, we have
[TABLE]
We point out even if is even then by the first supplement to quadratic reciprocity. Thus we have
[TABLE]
Here the first equality follows from (2.5). Finally, since does not divide , we obtain (A.1).
The formulas (A.3) - (A.7) follow from (A.1), (A.2) and Corollary 14 immediately. ∎
Appendix B Other formulas for and from symmetric polynomials
Since the sequences and are special values of and respectively, various formulas for and are derived immediately from specializations of some formulas for symmetric polynomials [M]. In this section, we list some typical formulas obtained from symmetric polynomials.
Generating functions
[TABLE]
Generating functions (B.1) and (B.2) are obtained by substituting (4.7) into (2.5) and (2.10) in [M].
Determinant formulas For convenience, put
[TABLE]
and
[TABLE]
From (2.5), (A.8) and the determinant formulas on p28 of [M], we obtain the following determinant formulas for and .
[TABLE]
Some relations For any partition let denote the product
[TABLE]
where is the number of parts of equal to . Then we have
[TABLE]
where run over partitions and denote the sum of the parts
[TABLE]
These formulas follow from (2.11) and (2.14*′*) in [M].
The reference list from the paper itself. Each links out to its DOI / PubMed record.
- 1[A] G. E. Andrews: Some formulae for the Fibonacci sequence with generalizations , Fibonacci Quart. 7 (1969), 113–130.
- 2[AAR] G. E. Andrews, R. Askey and R. Roy: Special Functions , @Cambridge University Press, 1999.
- 3[L] D. H. Lehmer: An extended theory of Lucas’ functions , Ann. of Math. 31 (1930), 419–448.
- 4[M] I. G. Macdonald: Symmetric Functions and Hall Polynomials , Oxford University Press, 1995.
- 5[S] B. E. Sagan: The Symmetric Group , GTM 203 , 2003.
