Gauss--Bonnet theorem for compact and orientable surfaces: a proof without using triangulations

A stereological version of the Gauss-Bonnet formula

We give a stereological version of the Gauss-Bonnet formula in order to compute the Euler characteristic of a domain with boundary in a smooth orientable surface in R^3, by looking at contacts with a "sweeping" plane.

The Gauss-Bonnet theorem for vector bundles

We give a short proof of the Gauss-Bonnet theorem for a real oriented Riemannian vector bundle $E$ of even rank over a closed compact orientable manifold $M$. This theorem reduces to the classical Gauss-Bonnet-Chern theorem in the special case when $M$ is a Riemannian manifold and $E$ is the tangent bundle of $M$ endowed with the Levi-Civita connection. The proof is based on an explicit geometric construction of the Thom class for 2-plane bundles.

单模随机无限 trivalent 双曲多面体的类高斯-博内二分法

A Gauss-Bonnet-Type Dichotomy for Unimodular Random Infinite Trivalent Hyperbolic Polyhedra

本文针对三维双曲空间中的单模随机无限 trivalent 双曲多面体，建立共形类型的统一几何概率理论，通过局部几何量的期望给出其全局共形类型的二分判据，还证明了有限多面体的 Benjamini-Schramm 极限的抛物性并得到面随机游走的双曲速度结论。

The Gauss map on translational Riemannian manifolds and the topology of hypersurfaces

We introduce the notion of translational Riemannian manifolds and define a Gauss map for orientable immersed hypersurfaces lying in these ambients, an associated translational curvature and prove a Gauss-Bonnet theorem. We also use this Gauss map to prove that if $M^{n}$ is a compact, connected and oriented immersed hypersurface of the unit sphere $\mathbb{S}^{n+1}$ ($n\geq2$) contained in a geodesic ball of radius $R$ and whose principal curvatures are strictly bigger than $\tan\left( R/2 \right)$, then $M$ is diffeomorphic to $\mathbb{S}^{n}$. Additionally, we show that for any $\varepsilon\…