 «THE BULLETIN OF IRKUTSK STATE UNIVERSITY». SERIES «MATHEMATICS»
«IZVESTIYA IRKUTSKOGO GOSUDARSTVENNOGO UNIVERSITETA». SERIYA «MATEMATIKA»
ISSN 1997-7670 (Print)
ISSN 2541-8785 (Online)

The Euler – Maclaurin Formula for Rational Parallelotope

Author(s)
O. A. Shishkina
Abstract

The problem of summation of functions of a discrete argument is one of the classical problems of the calculus of finite differences, for example, the sum of the sequence of power of natural numbers was computed by Bernoulli (1713), and his studies led to the development of several branches of combinatorial analysis. Euler (1733) and independently Maclaurin (1738) found a formula in which the required sum is expressed through derivatives and the integral of the given function. Its first rigorous proof was given by Jacobi (1834).

A natural summation of functions of several discrete arguments is over integer points of rational polytopes. The analogues of the Euler – Maclaurin formula for summation of polynomials over an arbitrary rational polytope and for summation of function of exponential type over integer points of simplex are known.

In this article we obtain a multidimensional analogue of the Euler-Maclaurin formula for summation of entire functions of exponential type over integer points of rational parallelotops built on generators of a unimodular rational cone. Unimodularity of the cone is essential since in the chosen method of proof it allows us to change variables and replace the parallelotope by the parallelepiped. Also, we implement Euler’s approach based on the concept of discrete primitive functions. Namely, using the methods of the theory of multidimensional difference equations, the concept of a generalized discrete primitive is introduced, and the methods of the theory of differential operators of infinite order allow to justify the convergence of series of functions that appear in the Euler – Maclaurin formula.

Keywords
unimodular rational cone, rational parallelotope, summation of functions, multidimensional difference equations, differential operators of infinite order
UDC
517.55+517.96
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