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In mathematics, a quasi-polynomial (pseudo-polynomial) is a generalization of polynomials. While the coefficients of a polynomial come from a ring, the coefficients of quasi-polynomials are instead periodic functions with integral period. Quasi-polynomials appear throughout much of combinatorics as the enumerators for various objects. A quasi-polynomial can be written as , where is a periodic function with integral period. If is not identically zero, then the degree of ''q'' is ''d''. Equivalently, a function is a quasi-polynomial if there exist polynomials such that when . The polynomials are called the constituents of ''f''. ==Examples== * Given a ''d''-dimensional polytope ''P'' with rational vertices , define ''tP'' to be the convex hull of . The function is a quasi-polynomial in ''t'' of degree ''d''. In this case, ''L(P,t)'' is a function . This is known as the Ehrhart quasi-polynomial, named after Eugène Ehrhart. * Given two quasi-polynomials ''F'' and ''G'', the convolution of ''F'' and ''G'' is : which is a quasi-polynomial with degree 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Quasi-polynomial」の詳細全文を読む スポンサード リンク
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