異種微分積分学における導函数と積分函数の一覧

ニュートンライプニッツによる古典的な微積分に代わるものは多く、無数にある非ニュートン微分積分学(英語版)の何れもがそのような例として挙げられる[1]。そういった代替微積分学のほうが、与えられた科学的・数学的な考えを言い表すのに通常の微積分学よりも適しているということが時折ある[2][3][4]

以下の表は「幾何微分積分学[注釈 1]と呼ばれる種類の乗法的微分積分学(英語版)(およびその離散版)を念頭に置いた。すなわち、乗法的微分は幾何微分、乗法的積分は幾何積分の意味で用い、差分は前進差分をとる:

各種微分積分学の対応関係
通常の微分積分学
(連続・加法的)
乗法的微分積分学
(連続・乗法的)
和分差分学
(離散・加法的)
乗法的和分差分学
(離散・乗法的)
導函数 微分 f ( x ) = lim h 0 f ( x + h ) f ( x ) h {\displaystyle f'(x)=\lim _{h\to 0}{f(x+h)-f(x) \over {h}}} 乗法的微分 f ( x ) = lim h 0 ( f ( x + h ) f ( x ) ) 1 h {\displaystyle f^{*}(x)=\lim _{h\to 0}{\left({f(x+h) \over {f(x)}}\right)^{1 \over {h}}}} 差分(difference) Δ f ( x ) = f ( x + 1 ) f ( x ) {\displaystyle \Delta f(x)\,=f(x+1)-f(x)} 乗法的差分
(multiplicative difference)[5] f ( x + 1 ) f ( x ) {\displaystyle {\frac {f(x+1)}{f(x)}}}
原始函数 不定積分 f ( x ) d x = f ( x ) + C {\displaystyle \int f'(x)\,dx=f(x)+C} 乗法的不定積分 f ( x ) d x = C f ( x ) {\displaystyle \int f^{*}(x)^{dx}=Cf(x)} 不定和分(antidifference) Δ 1 Δ f ( x ) = f ( x ) + C {\displaystyle \Delta ^{-1}\Delta f(x)=f(x)+C} 乗法的不定和分
(indefinite product)[6] x f ( x + 1 ) f ( x ) = C f ( x ) {\displaystyle \prod _{x}{\frac {f(x+1)}{f(x)}}=Cf(x)}

ただし C は任意定数(順に、積分定数、積分因数、和分定数、和分因数などと呼ばれる)。以下の表ではこれら任意定数は省略してある。

簡単な函数に対する各種の微分積分
通常の微分積分学 乗法的微分積分学 和分差分学 乗法的和分差分学
原関数 f ( x ) {\displaystyle f(x)} 微分 f ( x ) {\displaystyle f'(x)} 積分 f ( x ) d x {\displaystyle \int f(x)dx} 乗法的微分 f ( x ) {\displaystyle f^{*}(x)} 乗法的積分 f ( x ) d x {\displaystyle \int f(x)^{dx}} 前進差分 Δ f ( x ) {\displaystyle \Delta f(x)} 不定和分 Δ 1 f ( x ) {\displaystyle \Delta ^{-1}f(x)} 乗法的前進差分 乗法的不定和分 x f ( x ) {\displaystyle \prod _{x}f(x)}
定数函数: a {\displaystyle a} 0 {\displaystyle 0} a x {\displaystyle ax} 1 {\displaystyle 1} a x {\displaystyle a^{x}} 0 {\displaystyle 0} a x {\displaystyle ax} 1 {\displaystyle 1} a x {\displaystyle a^{x}}
恒等函数: x {\displaystyle x} 1 {\displaystyle 1} x 2 2 {\displaystyle {\frac {x^{2}}{2}}} e x {\displaystyle {\sqrt[{x}]{e}}} x x e x {\displaystyle {\frac {x^{x}}{e^{x}}}} 1 {\displaystyle 1} x 2 2 x 2 {\displaystyle {\frac {x^{2}}{2}}-{\frac {x}{2}}} 1 + 1 x {\displaystyle 1+{\frac {1}{x}}} Γ ( x ) {\displaystyle \Gamma (x)}
一次函数: a x + b {\displaystyle ax+b} a {\displaystyle a} a x 2 + 2 b x 2 {\displaystyle {\frac {ax^{2}+2bx}{2}}} exp ( a a x + b ) {\displaystyle \exp \left({\frac {a}{ax+b}}\right)} ( b + a x ) b a + x e x {\displaystyle {\frac {(b+ax)^{{\frac {b}{a}}+x}}{e^{x}}}} a {\displaystyle a} a x 2 + 2 b x a x 2 {\displaystyle {\frac {ax^{2}+2bx-ax}{2}}} 1 + a a x + b {\displaystyle 1+{\frac {a}{ax+b}}} a x Γ ( a x + b a ) Γ ( a + b a ) {\displaystyle {\frac {a^{x}\Gamma ({\frac {ax+b}{a}})}{\Gamma ({\frac {a+b}{a}})}}}
逆数函数: 1 x {\displaystyle {\frac {1}{x}}} 1 x 2 {\displaystyle -{\frac {1}{x^{2}}}} ln | x | {\displaystyle \ln |x|} 1 e x {\displaystyle {\frac {1}{\sqrt[{x}]{e}}}} e x x x {\displaystyle {\frac {e^{x}}{x^{x}}}} 1 x + x 2 {\displaystyle -{\frac {1}{x+x^{2}}}} ψ ( x ) {\displaystyle \psi (x)} x x + 1 {\displaystyle {\frac {x}{x+1}}} 1 Γ ( x ) {\displaystyle {\frac {1}{\Gamma (x)}}}
冪函数: x a {\displaystyle x^{a}} a x a 1 {\displaystyle ax^{a-1}} x a + 1 a + 1 {\displaystyle {\frac {x^{a+1}}{a+1}}} e a x {\displaystyle e^{\frac {a}{x}}} e a x x a x {\displaystyle e^{-ax}x^{ax}} ( x + 1 ) a x a {\displaystyle (x+1)^{a}-x^{a}} B a + 1 ( x ) a + 1 ( a Z ) {\displaystyle {\frac {B_{a+1}(x)}{a+1}}\quad (a\notin \mathbb {Z} ^{-})}
nor ( 1 ) a 1 ψ ( a 1 ) ( x ) Γ ( a ) {\displaystyle {\frac {(-1)^{a-1}\psi ^{(-a-1)}(x)}{\Gamma (-a)}}}
( 1 + 1 x ) a {\displaystyle \left(1+{\frac {1}{x}}\right)^{a}} Γ ( x ) a {\displaystyle \Gamma (x)^{a}}
指数函数: a x {\displaystyle a^{x}} a x ln a {\displaystyle a^{x}\ln a} a x ln a {\displaystyle {\frac {a^{x}}{\ln a}}} a {\displaystyle a} a x 2 2 {\displaystyle a^{\frac {x^{2}}{2}}} ( a 1 ) a x {\displaystyle (a-1)a^{x}} a x a 1 {\displaystyle {\frac {a^{x}}{a-1}}} a {\displaystyle a} a x 2 x 2 {\displaystyle a^{\frac {x^{2}-x}{2}}}
a x {\displaystyle {\sqrt[{x}]{a}}} a x ln a x 2 {\displaystyle -{\frac {{\sqrt[{x}]{a}}\ln a}{x^{2}}}} x a x Ei ( ln a x ) ln a {\displaystyle x{\sqrt[{x}]{a}}-\operatorname {Ei} \left({\frac {\ln a}{x}}\right)\ln a} a 1 x 2 {\displaystyle a^{-{\frac {1}{x^{2}}}}} a ln x {\displaystyle a^{\ln x}} a 1 1 + x a 1 x {\displaystyle a^{\frac {1}{1+x}}-a^{\frac {1}{x}}} ? {\displaystyle ?} a 1 x + x 2 {\displaystyle a^{-{\frac {1}{x+x^{2}}}}} a ψ ( x ) {\displaystyle a^{\psi (x)}}
対数函数: log a x {\displaystyle \log _{a}x} 1 x ln a {\displaystyle {\frac {1}{x\ln a}}} log a x x x ln a {\displaystyle \log _{a}x^{x}-{\frac {x}{\ln a}}} exp ( 1 x ln x ) {\displaystyle \exp \left({\frac {1}{x\ln x}}\right)} ( log a x ) x e li ( x ) {\displaystyle {\frac {(\log _{a}x)^{x}}{e^{\operatorname {li} (x)}}}} log a ( 1 x + 1 ) {\displaystyle \log _{a}\left({\frac {1}{x}}+1\right)} log a Γ ( x ) {\displaystyle \log _{a}\Gamma (x)} log x ( x + 1 ) {\displaystyle \log _{x}(x+1)} ? {\displaystyle ?}
x x {\displaystyle x^{x}} x x ( 1 + ln x ) {\displaystyle x^{x}(1+\ln x)} ? {\displaystyle ?} e x {\displaystyle ex} e 1 4 x 2 ( 1 2 ln x ) {\displaystyle e^{-{\frac {1}{4}}x^{2}(1-2\ln x)}} ( x + 1 ) x + 1 x x {\displaystyle (x+1)^{x+1}-x^{x}} ? {\displaystyle ?} ( x + 1 ) x + 1 x x {\displaystyle {\frac {(x+1)^{x+1}}{x^{x}}}} K ( x ) {\displaystyle \operatorname {K} (x)}
ガンマ函数: Γ ( x ) {\displaystyle \Gamma (x)} Γ ( x ) ψ ( x ) {\displaystyle \Gamma (x)\psi (x)} ? {\displaystyle ?} e ψ ( x ) {\displaystyle e^{\psi (x)}} e ψ ( 2 ) ( x ) {\displaystyle e^{\psi ^{(-2)}(x)}} ( x 1 ) Γ ( x ) {\displaystyle (x-1)\Gamma (x)} ( 1 ) x + 1 Γ ( x ) ( ! ( x ) ) {\displaystyle (-1)^{x+1}\Gamma (x)(!(-x))} x {\displaystyle x} Γ ( x ) x 1 K ( x ) {\displaystyle {\frac {\Gamma (x)^{x-1}}{\operatorname {K} (x)}}}
  • ψ ( x ) = Γ ( x ) Γ ( x ) {\displaystyle \psi (x)={\frac {\Gamma '(x)}{\Gamma (x)}}} ディガンマ関数
  • K ( x ) = e ζ ( 1 , x ) ζ ( 1 ) = e z z 2 2 + z 2 ln ( 2 π ) ψ ( 2 ) ( z ) {\displaystyle K(x)=e^{\zeta '(-1,x)-\zeta '(-1)}=e^{{\frac {z-z^{2}}{2}}+{\frac {z}{2}}\ln(2\pi )-\psi ^{(-2)}(z)}} K関数
  • ( ! x ) = Γ ( x + 1 , 1 ) e {\displaystyle (!x)={\frac {\Gamma (x+1,-1)}{e}}} モンモール数
  • B a ( x ) = a ζ ( a + 1 , x ) {\displaystyle B_{a}(x)=-a\zeta (-a+1,x)} は次数が実数に一般化されたベルヌイ多項式

である。

関連項目

注釈

  1. ^ 幾何代数(英語版)を一般化するものとして幾何解析[訳語疑問点] (geometric calculus) とも呼ばれる 重ベクトル解析(英語版、フランス語版)[訳語疑問点] と混同してはならない

出典

  1. ^ M. Grossman and R. Katz, Non-Newtonian Calculus, ISBN 0-912938-01-3, Lee Press, 1972.
  2. ^ Agamirza E. Bashirov, Emine Misirli Kurpinar, and Ali Ozyapici. "Multiplicative calculus and its applications", Journal of Mathematical Analysis and Applications, 2008.
  3. ^ Diana Andrada Filip and Cyrille Piatecki. "A non-Newtonian examination of the theory of exogenous economic growth", CNCSIS – UEFISCSU(project number PNII IDEI 2366/2008) and LEO, 2010.
  4. ^ Luc Florack and Hans van Assen."Multiplicative calculus in biomedical image analysis", Journal of Mathematical Imaging and Vision, DOI: 10.1007/s10851-011-0275-1, 2011.
  5. ^ H. R. Khatami & M. Jahanshahi & N. Aliev (2004). "An analytical method for some nonlinear difference equations by discrete multiplicative differentiation"., 5—10 July 2004, Antalya, Turkey – Dynamical Systems and Applications, Proceedings, pp. 455—462
  6. ^ M. Jahanshahi, N. Aliev and H. R. Khatami (2004). "An analytic-numerical method for solving difference equations with variable coefficients by discrete multiplicative integration"., 5—10 July 2004, Antalya, Turkey – Dynamical Systems and Applications, Proceedings, pp. 425—435