# What defines a deviation vector

1. Feb 5, 2015

### center o bass

In the last paragraph in Wald p. 224, he states that if one considers a timelike geodesic $\gamma$ with tangent field $\xi$ and $p \in \gamma$ and now looks at the congruence of geodesics passing through $p$, then every Jacobi field which vanishes at $p$ is a deviation field for this congruence.

Questions:

1. What properties actually defines a deviation field?
2. Why is the statement above true?

2. Feb 10, 2015

### Staff: Admin

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

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