Example image of eyePlorer eyePlorer map for 'Volume element': Cylindrical coordinate system Function (mathematics) Integral Mathematics Spherical coordinate system Volume Manifold Measure (mathematics) Differentiable manifold Differential form Orientability Volume form Absolute value Ricci curvature Equiareal map Solid of revolution Ensemble average Cusp neighborhood Unit tangent bundle Laplace–Beltrami operator Poincaré metric Kaluza–Klein theory N-sphere