Supplementary mathematics/Riemannian geometry

Riemannian geometry is a branch of differential geometry that investigates and studies the contents of Riemannian manifolds, i.e. smooth manifolds equipped with Riemannian metric, this manifold structure is equipped with inner multiplication on the tangent space at any point, so that from one point to The other point changes smoothly. Also, this structure specifically acquires local concepts such as angle, bend length, surface area and volume. From these, some other global quantities can be obtained by integration.