Abstract
In the 1970s, Gian-Carlo Rota constructed the umbral calculus for investigating the properties of special functions, and by Kim-Kim, umbral calculus is generalized called -umbral calculus. In this paper, we find some important relationships between degenerate Changhee polynomials and some important special polynomials by expressing the Changhee polynomial as a linear combination of some special polynomials. In addition, we derive some interesting identities related to degenerate poly-Changhee polynomials and some important special functions by using -umbral calculus.
1. Introduction
Let be an odd prime number, and let , and denote the ring of -adic rational integer, the field of -adic rational numbers, and the complication of the algebraic closure of , respectively. The -adic norm is normally defined by . As is known, the -adic invariant integral on is defined by Kim to bewhere is a continuous functions on (see [1]).
By using equation (1), the generation function of the Changhee polynomials is defined to be(see [2–4]). When , are called the Changhee numbers.
As one of the special polynomials, the Changhee polynomials and numbers are related closely some important special polynomials in the combinatorics, applied mathematics, mathematical physics, engineering, or economics. In [3], the authors found symmetric identities for that polynomials by using the fermionic -adic integral on , and some properties and zeros of these polynomials on the locally constant space were studied in [5]. In [4, 6], the authors generalized these polynomials to ring of -adic integer . Kim-Kim defined different Changhee polynomials named type 2 Changhee polynomials in [7] and found some relationships between those polynomials and Changhee polynomials, the Stirling numbers of the first and second kind, Euler polynomials and type 2 Euler polynomials. Moreover, in [2, 4, 8, 9], the authors studied the properties of degenerate version of Changhee polynomials, -Changhee polynomials, and Appell-type -Changhee polynomials, respectively.
For , the Stirling numbers of the first kind and the Stirling numbers of the second kind , respectively, are given bywhere and is the falling factorial sequences.
For each positive integer , it is well known (see [10]) that
For any nonzero real number , the degenerate exponential function is defined to be(see [7, 11, 12]) and let be the compositional inverse function of satisfying . Then, we have(see [12–16] where are -falling factorial of .
By using the degenerate exponential function, Carlitz defined the degenerate Bernoulli polynomials in [11, 17], and in recent years, studies of degenerate versions of some special polynomials have been increased by many researchers with their interests not only in combinatorial properties but also its applications (see [8, 9, 12–16, 18–21]).
As a degenerate version of the Stirling numbers of the first and second kind in equation (3), the degenerate Stirling numbers of the first kind and the degenerate Stirling numbers of the second kind are, respectively, introduced by Kim-Kim (see [8, 14–16, 19]) as follows:
The degenerate polyexponential functions are defined by Kim-Kim as(see [12, 18]). In particular, if , then, .
As a generalization of the degenerate exponential function, the degenerate polyexponential function is used by many researchers. In [15], Kim-Kim defined degenerate poly-Bell polynomials and provided explicit representations and combinatorial identities for these polynomials. Kurt defined the degenerate poly-Euler numbers and polynomials arising from the degenerate polyexponential functions and derived explicit relations for these numbers and polynomials (see [16]). In [14], Kim-Jang defined the degenerate poly-Genocchi polynomials and found some interesting identities of those polynomials.
Let be the field of complex numbers,and let
Let be the vector space of all linear functionals on .
Then, each gives rise to the linear functional on , called -linear functional given by , which is defined byand by linear extension (see [19]). From (11), we havewhere is Kronecker’s symbol.
For each and each , Kim-Kim defined the differential operator on in [19] byand for any ,
In addition, they showed that for , and ,
The order of is the smallest integer for which the coefficient of does not vanish. If , then is called invertible and such series has a multiplicative inverse of . If , then, is called delta series and it has a compositional inverse of with (see [22]).
Let be a delta series and let be an invertible series. Then, there exists a unique sequence of polynomials satisfying the orthogonality conditions:(see [19]). Here, is called the -Sheffer sequence for , which is denoted by . The sequence is the -Sheffer sequence for if and only if(see [19]) for all , where is the compositional inverse of such that .
Let and let . Then, by (16), we haveand thus, we know that
The following theorem is very useful tools in the -umbral calculus which is found by Kim and Kim (see [19]).
Theorem 1. Let and let . Ifthen,
Let . Since
By equation (22), we getand thus, we know that
In the similar way, we also know that
In this paper, we find some interesting identities about degenerate poly-Changhee polynomials, higher-order degenerate Bernoulli polynomials, degenerate Euler polynomials, degenerate Bell polynomials, degenerate Lah-Bell polynomials, degenerate Frobenius–Euler polynomials, and Mittag-Leffer polynomials by using -umbral calculus.
2. Degenerate Poly-Changhee Polynomials
The degenerate poly-Changhee polynomials are defined by the generating function:
In the special case , are called the degenerate poly-Changhee numbers.
By equation (17), we know that the -Sheffer sequences of degenerate poly-Changhee polynomials is
Theorem 2. For each non-negative integer , we have
Proof. Let . SinceBy Theorem 1, we getand thus, our theorem is proved.
Let . By (15) and (16),and soBy equations (24) and (27), we know thatand soNote thatwhere , , and are type 2 Bernoulli numbers which are defined by the generating function to be(see [7]) By equations (13) and (35), we know thatBy equation (36), we obtain the following theorem.
Theorem 3. For each , we have
Note that by Theorem 1 and equation (27), we get
Thus, by (39), we obtain the following theorem.
Theorem 4. For each non-negative integer , we haveBy using equation (17), the higher-order degenerate Bernoulli polynomials are defined by the generating function:(see [24, 25]). In the special case , are called the higher-order degenerate Bernoulli numbers.
By the definition of higher-order degenerate Bernoulli polynomials (41), we know thatIf we put , then, by the Theorem 1 and (42), we havewhere the higher-order degenerate Bernoulli numbers of the second kind are given.(see [26]). By equation (43), we obtain the following theorem.
Theorem 5. For each non-negative integer , we haveThe degenerate Euler polynomials are defined by the generating function:(see [24]). When , are called the degenerate Euler numbers.
By the definition of the degenerate Euler polynomials, we know thatLet . By Theorem 1 and (47), we get
Therefore, by equation (48), we obtain the following theorem.
Theorem 6. For each non-negative integer , we have
The fully degenerate Bell polynomials are defined as(see [12, 20]). By the definition of fully degenerate Bell polynomials, we note that
Note that
Let . By Theorem 1, equations (51), and (52), we getand thus, by equation (53), we obtain the following theorem.
Theorem 7. For each non-negative integer , we have
The degenerate Lah-Bell polynomials are defined by the generating function:(see [27]). In the special case , are called the Lah-Bell numbers.
By equation (55), we know the -Sheffer sequence of degenerate Lah-Bell polynomials is
Note that
Let . By Theorem 1, (56) and (57), we get
By equation (58), we obtain the following theorem.
Theorem 8. For each non-negative integer , we have
The degenerate Daehee polynomials are defined by the generating function:
By equation (60), we know that
Let . Then, by Theorem 1 and (61), we get
By equation (62), we obtain the following theorem.
Theorem 9. For each non-negative integer , we have
The degenerate Frobenius–Euler polynomials of order defined by the generating function to be(see [1, 19, 30]). In the special case , are called the degenerate Frobenius–Euler numbers of order .
By equation (64), we know the -Sheffer sequence of degenerate Frobenius–Euler polynomials is
Let . Then, by Theorem 1, equations (27) and (65), we haveand so by (66), we obtain the following theorem.
Theorem 10. For each non-negative integer , we have
The Mittag-Leffler polynomials are defined by the generating function to be
By the definition of Mittag-Leffler polynomials, we see that
Let . Then, by Theorem 1, equations (27) and (69), we haveand so by (70), we obtain the following theorem.
Theorem 11. For each non-negative integer , we have
3. Conclusion
In 1970s Gian-Carlo Rota constructed the important tools, called umbral calculus, for investigating the properties of special functions which was based on a linear functional, a linear differential operator, and adjoint (see [22]). In 2021, Kim-Kim generalized the umbral calculus to -umbral calculus, and -umbral calculus has been used as an important tool to study special functions by many researchers.
In this paper, we find some important relationships between degenerate Changhee polynomials and some important special polynomials by expressing the Changhee polynomial as a linear combination of higher-order degenerate Bernoulli polynomials, degenerate Euler polynomials, degenerate Bell polynomials, degenerate Lah-Bell polynomials, degenerate Frobenius–Euler polynomials or Mittag-Leffer polynomials.
If the methods used in this paper are applied to expandable polynomials using polyexponential functions, many new and interesting identities can be found.
Data Availability
No data were used to support this study.
Conflicts of Interest
The authors declare that they have no competing interests.
Authors’ Contributions
J. W. P. conceived of the framework and structured the whole paper. S. J. Y. and J. W. P. wrote the paper. All authors have read and agreed to the published version of the manuscript.
Acknowledgments
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) NRF-2020R1F1A1A01075658.