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Riemann curvature four-tensor
Definition
Let be a Riemannian manifold, let be its unique Levi–Civita connection, and let be the curvature tensor with the sign fixed above. The Riemann curvature four-tensor is the covariant tensor
Thus the first two arguments are the two differentiating slots, the third is the field acted on, and the fourth lowers the output index. In coordinates, if , then under this argument order. This convention makes positive on a positively curved round sphere.
The definition uses no chosen frame. On an empty or zero-dimensional manifold it gives the unique zero four-tensor; in dimension one the same formula applies and later symmetries force it to vanish. It is valid up to the boundary when a Riemannian manifold with boundary is supplied.
Depends on
Used by
- Bonnet-Myers fundamental group is finite Corollary
- Diameter rigidity from toponogov under a sectional lower bound Corollary
- Upper sectional curvature bounds delay conjugate points Corollary
- Ricci lower bound does not control every sectional curvature in dimension at least three Counterexample
- Index form of a geodesic segment Definition
- Jacobi field Definition
- Radial Jacobi tensor Definition
- Ricci curvature Definition
- Sectional curvature Definition
- A deformed sphere has the same total curvature Example
- A flat torus showing simple connectedness is needed for global exp injectivity Example
- Bonnet-Myers for the round sphere Example
- Cartan hadamard for hyperbolic space Example
- Curvature of a Riemannian product Example
- Distance hessian and laplacian in space forms Example
- Gaussian curvature of a surface of revolution Example
- Hyperbolic space has negative constant sectional curvature Example
- The round two-sphere has zero untwisted Spin Dirac kernel Example
- Cartan hadamard says exp p is injective without simple connectedness False statement
- Positive ricci curvature without a uniform lower bound implies compactness False statement
- Ricci curvature and scalar curvature determine the full Riemann tensor in every dimension False statement
- Lichnerowicz formula for a geometric Dirac operator Lemma
- Spinor and geometric Clifford bundles and connections are well defined Lemma
- Surface geodesic flow, index form, and transport primitive Lemma
- Wronskian of two jacobi fields is constant Lemma
- Cartan decomposition gives the invariant metric and curvature of G mod K Proposition
- Flat torus model geometry Proposition
- Hessian of distance in terms of radial jacobi fields Proposition
- Jacobi fields are the null solutions of the index form with fixed endpoints Proposition
- Jacobi fields are the null solutions of the index form with fixed endpoints Proposition
- Rigidity in bishop gromov on an interval Proposition
- Rigidity in rauch comparison Proposition
- Upper half-space model geometry Proposition
- A Riemannian manifold is flat iff it is locally isometric to Euclidean space Theorem
- Algebraic symmetries of the Riemann tensor Theorem
- Bonnet conjugate radius theorem Theorem
- Bonnet myers Theorem
- Differential second Bianchi identity Theorem
- Existence and uniqueness of jacobi fields from initial data Theorem
- Gauss equation for a Riemannian submanifold Theorem
…and 7 more results.
Dependency tree · two levels
9 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Ved Datar, Lectures on Riemannian Geometry (standard reference, not scraped)
- John M. Lee, Riemannian Manifolds: An Introduction to Curvature (standard reference, not scraped)