N차원 구면

개요

• 반지름 r인 n-차원 구면(n-sphere)
  
  • (n+1)-차원 유클리드 공간에서 다음 을 만족시키는 점들의 집합 \(x_1^2+\cdots+x_{n+1}^2= r^2\)

 

매개화

1차원 구면 \(S^1\)

\(\begin{array}{ccc} x_1 & = & r \cos (\theta ) \\ x_2 & = & r \sin (\theta ) \end{array}\) \(0\leq \theta \leq 2\pi\)

야코비안 \(r\)

• 원의 매개화와 삼각함수의 탄생 참조

 

2차원 구면 \(S^2\)

\(\begin{array}{ccc} x_1 & = & r \cos (\theta ) \sin \left(\phi _1\right) \\ x_2 & = & r \sin (\theta ) \sin \left(\phi _1\right) \\ x_3 & = & r \cos \left(\phi _1\right) \end{array}\) 야코비안 \(r^2 \sin \left(\phi _1\right)\) \(0\leq \theta \leq 2\pi\), \(0\leq \phi_1 \leq \pi\)

 

3차원 구면 \(S^3\)

\(\begin{array}{ccc} x_1 & = & r \cos (\theta ) \sin \left(\phi _1\right) \sin \left(\phi _2\right) \\ x_2 & = & r \sin (\theta ) \sin \left(\phi _1\right) \sin \left(\phi _2\right) \\ x_3 & = & r \sin \left(\phi _2\right) \cos \left(\phi _1\right) \\ x_4 & = & r \cos \left(\phi _2\right) \end{array}\) 야코비안 \(r^3 \sin \left(\phi _1\right) \sin ^2\left(\phi _2\right)\) \(0\leq \theta \leq 2\pi\), \(0\leq \phi_1,\phi_2 \leq \pi\)

 

4차원 구면 \(S^4\)

\(\begin{array}{ccc} x_1 & = & r \cos (\theta ) \sin \left(\phi _1\right) \sin \left(\phi _2\right) \sin \left(\phi _3\right) \\ x_2 & = & r \sin (\theta ) \sin \left(\phi _1\right) \sin \left(\phi _2\right) \sin \left(\phi _3\right) \\ x_3 & = & r \sin \left(\phi _2\right) \sin \left(\phi _3\right) \cos \left(\phi _1\right) \\ x_4 & = & r \sin \left(\phi _3\right) \cos \left(\phi _2\right) \\ x_5 & = & r \cos \left(\phi _3\right) \end{array}\) 야코비안 \(r^4 \sin \left(\phi _1\right) \sin ^2\left(\phi _2\right) \sin ^3\left(\phi _3\right)\) \(0\leq \theta \leq 2\pi\), \(0\leq \phi_1,\phi_2,\phi_3 \leq \pi\)  

단위구면의 부피에의 응용

• n차원 구면의 매개화
  다음의 점화식을 얻을 수 있다\[ \omega_{n}=\omega_{n-1}\left(\int_0^{\pi }\sin ^{n-1} \phi \, d\phi\right)=\omega_{n-1}\frac{\sqrt{\pi } \Gamma \left(\frac{n}{2}\right)}{\Gamma \left(\frac{n+1}{2}\right)}\]\[\omega_1=2\pi \]
  

역사

 

• http://www.google.com/search?hl=en&tbs=tl:1&q=
• 수학사 연표

 

 

메모

• 역행렬

$$ \left( \begin{array}{cccccccc} \cos \theta _1 & \left(\sin \theta _1\right) \left(\cos \theta _2\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\cos \theta _3\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\cos \theta _4\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\cos \theta _5\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\cos \theta _6\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\cos \theta _7\right) & \left(\sin \theta _1\right) \left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\sec \theta _8\right) \\ -\frac{\sin \theta _1}{r} & \frac{\left(\cos \theta _1\right) \left(\cos \theta _2\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\cos \theta _1\right) \left(\cos \theta _3\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\cos \theta _1\right) \left(\cos \theta _4\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\cos \theta _1\right) \left(\cos \theta _5\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\cos \theta _1\right) \left(\cos \theta _6\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\cos \theta _1\right) \left(\cos \theta _7\right)}{r} & \frac{\left(\sin \theta _2\right) \left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\cos \theta _1\right) \left(\sec \theta _8\right)}{r} \\ 0 & -\frac{\left(\sin \theta _2\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\cos \theta _2\right) \left(\cos \theta _3\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\sin \theta _3\right) \left(\cos \theta _2\right) \left(\cos \theta _4\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\cos \theta _2\right) \left(\cos \theta _5\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\cos \theta _2\right) \left(\cos \theta _6\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\cos \theta _2\right) \left(\cos \theta _7\right) \left(\csc \theta _1\right)}{r} & \frac{\left(\sin \theta _3\right) \left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\cos \theta _2\right) \left(\csc \theta _1\right) \left(\sec \theta _8\right)}{r} \\ 0 & 0 & -\frac{\left(\sin \theta _3\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right)}{r} & \frac{\left(\cos \theta _3\right) \left(\cos \theta _4\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right)}{r} & \frac{\left(\sin \theta _4\right) \left(\cos \theta _3\right) \left(\cos \theta _5\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right)}{r} & \frac{\left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\cos \theta _3\right) \left(\cos \theta _6\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right)}{r} & \frac{\left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\cos \theta _3\right) \left(\cos \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right)}{r} & \frac{\left(\sin \theta _4\right) \left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\cos \theta _3\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\sec \theta _8\right)}{r} \\ 0 & 0 & 0 & -\frac{\left(\sin \theta _4\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right)}{r} & \frac{\left(\cos \theta _4\right) \left(\cos \theta _5\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right)}{r} & \frac{\left(\sin \theta _5\right) \left(\cos \theta _4\right) \left(\cos \theta _6\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right)}{r} & \frac{\left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\cos \theta _4\right) \left(\cos \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right)}{r} & \frac{\left(\sin \theta _5\right) \left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\cos \theta _4\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\sec \theta _8\right)}{r} \\ 0 & 0 & 0 & 0 & -\frac{\left(\sin \theta _5\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right)}{r} & \frac{\left(\cos \theta _5\right) \left(\cos \theta _6\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right)}{r} & \frac{\left(\sin \theta _6\right) \left(\cos \theta _5\right) \left(\cos \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right)}{r} & \frac{\left(\sin \theta _6\right) \left(\sin \theta _7\right) \left(\cos \theta _5\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\sec \theta _8\right)}{r} \\ 0 & 0 & 0 & 0 & 0 & -\frac{\left(\sin \theta _6\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\csc \theta _5\right)}{r} & \frac{\left(\cos \theta _6\right) \left(\cos \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\csc \theta _5\right)}{r} & \frac{\left(\sin \theta _7\right) \left(\cos \theta _6\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\csc \theta _5\right) \left(\sec \theta _8\right)}{r} \\ 0 & 0 & 0 & 0 & 0 & 0 & -\frac{\left(\sin \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\csc \theta _5\right) \left(\csc \theta _6\right)}{r} & \frac{\left(\cos \theta _7\right) \left(\csc \theta _1\right) \left(\csc \theta _2\right) \left(\csc \theta _3\right) \left(\csc \theta _4\right) \left(\csc \theta _5\right) \left(\csc \theta _6\right) \left(\sec \theta _8\right)}{r} \\ \end{array} \right) $$  

관련된 항목들

• N차원 구면의 부피(면적)
• 자코비안

 

매스매티카 파일 및 계산 리소스

• https://docs.google.com/file/d/0B8XXo8Tve1cxakJjVmNBWHh2VTg/edit

   

관련논문

• Bruno P. Zimmermann, On topological actions of finite groups on S^3, arXiv:1606.07626 [math.GT], June 24 2016, http://arxiv.org/abs/1606.07626
• Chapling, Richard. “A Hypergeometric Integral with Applications to the Fundamental Solution of Laplace’s Equation on Hyperspheres.” arXiv:1508.06689 [math-Ph], August 26, 2015. http://arxiv.org/abs/1508.06689.