Articolele autorului Mircea Merca
Link la profilul stiintific al lui Mircea Merca

A note on the r-Whitney numbers of Dowling lattices

The complete and elementary symmetric functions are specializations of Schur functions. In this paper, we use this fact to give two identities for the complete and elementary symmetric functions. This result can be used to proving and discovering some algebraic identities involving r-Whitney and other special numbers.

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A note on the Jacobi-Stirling numbers

The Jacobi–Stirling numbers of both kinds are specializations of elementary and complete homogeneous symmetric functions. We use this fact to discover and prove some algebraic identities involving Jacobi–Stirling numbers. The Legendre–Stirling numbers are very special cases of the Jacobi–Stirling numbers. New connections between the Legendre–Stirling numbers and the central factorial numbers of odd indices are presented.

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A note on q-Stirling numbers

The q-Stirling numbers of both kinds are specializations of the complete or elementary symmetric functions. In this note, we use this fact to prove that the q-Stirling numbers can be expressed in terms of the q-binomial coefficients and vice versa.

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A note on the determinant of a Toeplitz-Hessenberg matrix

The nth-order determinant of a Toeplitz-Hessenberg matrix is expressed as a sum over the integer partitions of n. Many combinatorial identities involving integer partitions and multinomial coefficients can be generated using this formula.

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A generalization of the symmetry between complete and elementary symmetric functions

A generalization for the symmetry between complete symmetric functions and elementary symmetric functions is given. As corollaries we derive the inverse of a triangular Toeplitz matrix and the expression of the Toeplitz-Hessenberg determinant. A very large variety of identities involving integer partitions and multinomial coefficients can be generated using this generalization. The partitioned binomial theorem and a new formula for the partition

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Integer partitions and directed acyclic graphs

The algorithms for generating the integer partitions of a positive integer have long been invented. Nevertheless, data structures for storing the integer partitions are not received due attention. In 2005 there were introduced diagram structures to store integer partitions. In this article, we present a recently obtained result in storing integer partitions: the binary diagrams.

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A convolution for complete and elementary symmetric functions

In this paper we give a convolution identity for complete and elementary symmetric functions. This result can be used to prove and discover some combinatorial identities involving r-Stirling numbers, r-Whitney numbers and q-binomial coefficients. As a corollary we derive a generalization of the quantum Vandermonde's convolution identity.

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On some power sums of sine or cosine

In this note, using the multisection series method, we establish the formulas for various power sums of sine or cosine functions.

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On a trigonometrical sum

In 1966, J. M. Quoniam proposed Problem E1937 in the problems section of The American Mathematical Monthly. In this note we prove that the statement of this problem is incomplete, because the proposed identity is true only under certain conditions. Furthermore we show that this identity is a special case of a more general identity. Several related identities are also presented.

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An Asymptotic Formula of Cosine Power Sums

In the paper, the authors find several accurate approximations of some cosine power sums and present an asymptotic formula for these cosine power sums.

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