How to Derive the Dual Frame Vector in Terms of Connection Components?

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Homework Help Overview

The discussion revolves around deriving the expression for the derivative of a dual frame vector in terms of connection components, using the relation between dual vectors and the Leibniz rule.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of the relation ##\langle \vec e^a, \vec e_b \rangle = \delta^a_b## and how it relates to the derivative of dual frame vectors.
  • There is uncertainty about how to incorporate connection components without relying on a previously presented definition.
  • Some participants question the distinction between the derivatives of dual basis vectors and tangent basis vectors.

Discussion Status

The discussion is ongoing, with participants examining different interpretations of the relationships involved. Some have provided insights into the mathematical expressions, while others are seeking clarification on the definitions and assumptions being used.

Contextual Notes

There is mention of a specific definition regarding the derivative of the dual basis vector, which may influence the discussion. Participants are also navigating the complexities of the relationship between dual and tangent basis vectors.

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Homework Statement



Use the relation ##\langle \vec e^a, \vec e_b \rangle = \delta^a_b## and the Leibniz rule to give an expression for the derivative of a dual frame vector ##\frac{\partial \vec e_b}{\partial x^a}## in terms of the connexion components.

Homework Equations

The Attempt at a Solution



I'm not sure how to do this, but this is what I've got so far:

##\partial_c \langle \vec e^a, \vec e_b \rangle = 0##

##\langle \partial_c \vec e^a, \vec e_b \rangle + \langle \vec e^a, \partial_c \vec e_b \rangle = 0##

##\langle -\Gamma^b_{dc} \vec e^d, \vec e_b \rangle + \langle \vec e^a, \Gamma^d_{bc} \vec e_d \rangle = 0##

##\Gamma^d_{bc}\langle \vec e^a, \vec e_d \rangle - \Gamma^b_{dc} \langle \vec e^d, \vec e_b \rangle = 0##
 
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BOAS said:
##\langle \partial_c \vec e^a, \vec e_b \rangle + \langle \vec e^a, \partial_c \vec e_b \rangle = 0##

##\langle -\Gamma^b_{dc} \vec e^d, \vec e_b \rangle + \langle \vec e^a, \Gamma^d_{bc} \vec e_d \rangle = 0##
Between these lines you are using what you are supposed to show ...
 
Orodruin said:
Between these lines you are using what you are supposed to show ...

##\frac{\partial \vec e_b}{\partial x^a} = \Gamma^c_{ba} \vec e_c## was presented as a definition to me, so I'm not sure how I can bring in the connection components without using that fact. (Though I do appreciate your point)
 
That is not the derivative of the dual basis vector, it is the derivative of the tangent basis vector.
 

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