ExponentialGeneratingFunction[expr,n,x]
数列の n
番目の項が式 expr で与えられる x における指数型母関数を与える.
ExponentialGeneratingFunction[expr,{n1,n2,…},{x1,x2,…}]
n1, n2, … 番目の項が expr で与えられる x1, x2, … における多次元指数型母関数を与える.
ExponentialGeneratingFunction
ExponentialGeneratingFunction[expr,n,x]
数列の n
番目の項が式 expr で与えられる x における指数型母関数を与える.
ExponentialGeneratingFunction[expr,{n1,n2,…},{x1,x2,…}]
n1, n2, … 番目の項が expr で与えられる x1, x2, … における多次元指数型母関数を与える.
詳細とオプション

番目の項が
である数列の指数型母関数は
で与えられる.- 多次元の指数型母関数は
で与えられる. - 使用できるオプション
-
Assumptions $Assumptions パラメータについての仮定 GenerateConditions False パラメータについての条件を含む答を生成するかどうか Method Automatic 使用するメソッド VerifyConvergence True 収束を確かめるかどうか
例題
すべて開く すべて閉じる例 (1)
スコープ (19)
基本的な用法 (6)
ExponentialGeneratingFunction[a ^ n, n, z]ExponentialGeneratingFunction[a ^ (n + m), {n, m}, {z, w}]F = ExponentialGeneratingFunction[n (n + 1)(-1 / 2) ^ n, n, z]Plot3D,ContourPlot,またはDensityPlotを使って大きさをプロットする:
Block[{z = u + I v}, Table[plot[Abs[F], {u, -2, 2}, {v, -2, 2}], {plot, {Plot3D, ContourPlot, DensityPlot}}]]Block[{z = u + I v}, Table[plot[Arg[F], {u, -2, 2}, {v, -2, 2}], {plot, {Plot3D, ContourPlot, DensityPlot}}]]ExponentialGeneratingFunction[a n!, n, z, GenerateConditions -> True]With[{z = u + I v}, RegionPlot[Abs[z] < 1, {u, -2, 2}, {v, -2, 2}]]F = ExponentialGeneratingFunction[Sin[n 2Pi / 3](2 / 3) ^ n, n, Exp[I ω]]LogPlot[Abs[F] ^ 2, {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}]Plot[Arg[F], {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}]LogPlot[Abs[F] ^ 2, {ω, 0, 2π}, Ticks -> {{0, π, 2π}, Automatic}, ColorFunction -> Function[ω, Evaluate@Hue[Arg[F] / (2Pi) + 1 / 2]], ColorFunctionScaling -> False, Filling -> Axis]ParametricPlot3Dを使って複素平面のスペクトルをプロットする:
ParametricPlot3D[{Cos[ω], Sin[ω], Log[10, Abs[F] ^ 2]}, {ω, 0, 2π}, BoxRatios -> {1, 1, 1}]ExponentialGeneratingFunctionは,線形性を含む複数の特性を使用する:
ExponentialGeneratingFunction[a f[n] + b g[n], n, z]{ExponentialGeneratingFunction[a ^ n f[n], n, z], ExponentialGeneratingFunction[b ^ (-n)f[n], n, z]}ExponentialGeneratingFunction[Exp[I ω n]f[n], n, z]{ExponentialGeneratingFunction[ n f[n], n, z], ExponentialGeneratingFunction[n(n + 1) f[n], n, z]}ExponentialGeneratingFunction[Conjugate[f[n]], n, z]ExponentialGeneratingFunctionは自動的にリストに縫い込まれる:
ExponentialGeneratingFunction[{a ^ n, b ^ n}, n, z]ExponentialGeneratingFunction[{{a ^ n, b ^ n}, {n, n ^ 2}}, n, z]ExponentialGeneratingFunction[a ^ n == f[n], n, z]ExponentialGeneratingFunction[f[n] -> a ^ n, n, z]特殊数列 (13)
{ExponentialGeneratingFunction[UnitStep[n], n, z], ExponentialGeneratingFunction[UnitStep[n - 3], n, z]}Table[DiscretePlot[f, {n, -10, 10}], {f, {UnitStep[n], UnitStep[n - 3]}}]{ExponentialGeneratingFunction[n UnitStep[n], n, z], ExponentialGeneratingFunction[(n - 3)UnitStep[n - 3], n, z]}Table[DiscretePlot[f, {n, -10, 10}], {f, {n UnitStep[n], (n - 3)UnitStep[n - 3]}}]{ExponentialGeneratingFunction[n, n, z], ExponentialGeneratingFunction[n ^ 2, n, z]}ExponentialGeneratingFunction[Pochhammer[n, Range[0, 3]], n, z]ExponentialGeneratingFunction[FactorialPower[n, Range[0, 3]], n, z]ExponentialGeneratingFunction[a ^ n, n, z]ExponentialGeneratingFunction[a ^ n UnitStep[n - 2], n, x]{ExponentialGeneratingFunction[n a ^ n, n, z], ExponentialGeneratingFunction[n ^ 2 a ^ n, n, z]}Table[DiscretePlot[f, {n, 0, 40}], {f, {n (10 / 12) ^ n, n ^ 2 (10 / 12) ^ n}}]ExponentialGeneratingFunction[Pochhammer[n, Range[0, 3]] a ^ n, n, z]ExponentialGeneratingFunction[FactorialPower[n, Range[0, 3]] a ^ n, n, z]{ExponentialGeneratingFunction[Sin[ω n + ϕ], n, z], ExponentialGeneratingFunction[Cos[ω n + ϕ], n, z]}Table[DiscretePlot[f, {n, -20, 20}], {f, {Sin[2π / 10 n], Cos[2π / 10 n]}}]{ExponentialGeneratingFunction[(5 / 6) ^ n Sin[ω n], n, z], ExponentialGeneratingFunction[n (5 / 6) ^ n Sin[ω n], n, z]}Table[DiscretePlot[f, {n, 0, 20}], {f, {(5 / 6) ^ n Sin[2π / 10 n], n (5 / 6) ^ n Sin[2π / 10 n]}}]ExponentialGeneratingFunction[n ^ 2 a ^ n + b ^ n Sin[ω n] UnitStep[n - 2], n, z]DiscretePlot[n ^ 2 (5 / 6) ^ n + (11 / 12) ^ n 20Sin[2Pi / 10 n]UnitStep[n - 2], {n, 0, 50}]ExponentialGeneratingFunction[n (UnitStep[n] - UnitStep[n - 6]) + a ^ n UnitStep[n - 6], n, z]ExponentialGeneratingFunction[Piecewise[{{n, n ≤ 5}, {a ^ n, True}}], n, z]Simplify[%% - %]ExponentialGeneratingFunction[1 / (n + 1), n, z]ExponentialGeneratingFunction[(n^2 + n + 1) / (n + 1) ^ 2, n, z]ExponentialGeneratingFunction[FactorialPower[n, -2], n, z]ExponentialGeneratingFunction[a ^ n / (n + 1) ^ 2, n, z]ExponentialGeneratingFunction[a ^ n FactorialPower[n, -2], n, z]ExponentialGeneratingFunction[1 / n!, n, z]DiscreteRatioはすべての超幾何項数列について有理である:
DiscreteRatio[1 / n!, n]hl = {a ^ n, n!, Gamma[n], Pochhammer[a, n], FactorialPower[a, n], Binomial[n, a], Binomial[b, n], CatalanNumber[n]};DiscreteRatio[hl, n]DiscreteRatio[Times@@RandomChoice[hl, 3], n]ExponentialGeneratingFunction[(2^-2 + n/Gamma[(1/2) + n]), n, z]ExponentialGeneratingFunction[n / Binomial[2n, n], n, z]ExponentialGeneratingFunction[(FactorialPower[a1, n]/FactorialPower[b1, n]FactorialPower[b2, n]), n, z]ExponentialGeneratingFunction[Pochhammer[n, k], n, x]ExponentialGeneratingFunction[n! / CatalanNumber[n], n, x]ExponentialGeneratingFunction[LegendreP[n, a], n, z]DifferenceRootReduce[LegendreP[n, a], n]ExponentialGeneratingFunction[ChebyshevT[n, x], n, z]ExponentialGeneratingFunction[ChebyshevU[2n, x] ^ 2, n, z]DifferenceRootは,一般に,結果としてDifferentialRoot関数になる:
ExponentialGeneratingFunction[DifferenceRoot[Function[{y, m}, {y[m + 2] == y[m + 1] + y[m], y[0] == 0, y[1] == 1}]][n], n, z]ExponentialGeneratingFunction[BernoulliB[n], n, x]ExponentialGeneratingFunction[EulerE[n], n, x]ExponentialGeneratingFunction[Fibonacci[n] / n!, n, z]ExponentialGeneratingFunction[HarmonicNumber[n] / n!, n, z]ExponentialGeneratingFunction[Mod[n, 3], n, z]ExponentialGeneratingFunction[Exp[n 2π I / 3], n, z]ExponentialGeneratingFunction[Mod[n ^ 2, 5] ^ 3, n, x]ExponentialGeneratingFunction[a^n + m, {n, m}, {u, v}]ExponentialGeneratingFunction[n ^ 2 m ^ 3, {n, m}, {u, v}]ExponentialGeneratingFunction[a^n + mn ^ 2 m ^ 3, {n, m}, {u, v}]ExponentialGeneratingFunction[Sin[n + m]a ^ n, {n, m}, {u, v}]ExponentialGeneratingFunction[m / (n + 1), {n, m}, {u, v}]ExponentialGeneratingFunction[Mod[n + m, 2], {n, m}, {u, v}]一般化と拡張 (1)
オプション (5)
GenerateConditions (1)
デフォルトで,母関数がどこで収束するかに関する条件は与えられない:
ExponentialGeneratingFunction[(n + 1)!, n, x]GenerateConditionsを使って妥当条件を生成する:
ExponentialGeneratingFunction[(n + 1)!, n, x, GenerateConditions -> True]Method (1)
VerifyConvergence (3)
VerifyConvergenceをFalseに設定すると,母関数が形式オブジェクトとして扱われる:
ExponentialGeneratingFunction[n! 2 ^ n, n, x, VerifyConvergence -> False]VerifyConvergenceをTrueに設定すると,収束半径がゼロではないことが確かめられる:
ExponentialGeneratingFunction[n ! 2 ^ n, n, x, VerifyConvergence -> True]さらにGenerateConditionsをTrueに設定すると,収束条件が表示される:
ExponentialGeneratingFunction[n ! 2 ^ n, n, x, VerifyConvergence -> True, GenerateConditions -> True]特性と関係 (3)
ExponentialGeneratingFunctionは事実上無限和を計算する:
ExponentialGeneratingFunction[n ^ 2, n, z]Sum[n ^ 2 / n! z ^ n, {n, 0, Infinity}]ExponentialGeneratingFunction[a f[n] + b g[n], n, z]ExponentialGeneratingFunctionはGeneratingFunctionと密接な関係がある:
{ExponentialGeneratingFunction[n, n, z], GeneratingFunction[n / n!, n, z]}{ExponentialGeneratingFunction[n, n, z], ZTransform[n / n!, n, 1 / z]}{ExponentialGeneratingFunction[n, n, Exp[-I ω]], FourierSequenceTransform[n UnitStep[n] / n!, n, ω]}考えられる問題 (1)
ExponentialGeneratingFunctionはパラメータのすべての値については収束しないかもしれない:
{Sum[a ^ n n! x ^ n / n! /. {a -> 2, x -> 1}, {n, 0, ∞}], ExponentialGeneratingFunction[2 ^ n n!, n, 1]}ExponentialGeneratingFunction[a ^ n n!, n, x]GenerateConditionsを使って収束領域を得る:
ExponentialGeneratingFunction[n! a ^ n, n, x, GenerateConditions -> True]おもしろい例題 (1)
flist = {{UnitStep[n + 1 / 2], n, z}, {n ^ 2 + 2, n, z}, {1 / (2n + 1), n, z}, {Sin[a n], n, z}, {ChebyshevT[n, a], n, z}, {HarmonicNumber[n] / n!, n, z}, {a ^ n Sin[n], n, z}, {Mod[n, 4], n, z}, {Power[m, n], {m, n}, {u, v}}, {m / (n + 1), {m, n}, {u, v}}};Grid[Prepend[{#[[1]], ExponentialGeneratingFunction@@#}& /@ flist, {f, "Exponential Generating Function"}], IconizedObject[«Grid options»]]//TraditionalFormテキスト
Wolfram Research (2008), ExponentialGeneratingFunction, Wolfram言語関数, https://reference.wolfram.com/language/ref/ExponentialGeneratingFunction.html.
CMS
Wolfram Language. 2008. "ExponentialGeneratingFunction." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ExponentialGeneratingFunction.html.
APA
Wolfram Language. (2008). ExponentialGeneratingFunction. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ExponentialGeneratingFunction.html
BibTeX
@misc{reference.wolfram_2026_exponentialgeneratingfunction, author="Wolfram Research", title="{ExponentialGeneratingFunction}", year="2008", howpublished="\url{https://reference.wolfram.com/language/ref/ExponentialGeneratingFunction.html}", note=[Accessed: 15-September-2026]}
BibLaTeX
@online{reference.wolfram_2026_exponentialgeneratingfunction, organization={Wolfram Research}, title={ExponentialGeneratingFunction}, year={2008}, url={https://reference.wolfram.com/language/ref/ExponentialGeneratingFunction.html}, note=[Accessed: 15-September-2026]}