Definition:Critical Point of Riemannian Length
Jump to navigation
Jump to search
Definition
Let $\struct {M, g}$ be a Riemannian manifold.
Let $I = \closedint a b$ be a closed real interval.
Let $J \subseteq \R$ be an open real interval.
Let $\gamma : I \to M$ be an admissible curve.
Let $L_g$ be the Riemannian length of some admissible curve.
Let $\Gamma : J \times I \to M$ be the proper variation of $\gamma$ such that:
- $\forall s \in J, \forall t \in I : \tuple {s, t} \stackrel {\Gamma}{\mapsto} \map {\Gamma_s} t$
Suppose:
- $\forall \Gamma : \ds \dfrac d {d s} \map {L_g} {\Gamma_s} = 0$
Then $\gamma$ is called the critical point of $L_g$.
Sources
- 2018: John M. Lee: Introduction to Riemannian Manifolds (2nd ed.) ... (previous) ... (next): $\S 6$: Geodesics and Distance. Minimizing Curves Are Geodesics