calculate the geodesic equations for a symmetric linear connection on the tangent bundle - Maple Help

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Tensor[GeodesicEquations] - calculate the geodesic equations for a symmetric linear connection on the tangent bundle

Calling Sequences

     GeodesicEquations (C, Gamma, t)

Parameters

   C       - a list of functions of a single variable, defining the components of a curve on a manifold M with respect to a given system of coordinates

   Gamma   - a connection on the tangent bundle to a manifold M

   t       - the curve parameter

 

Description

Examples

See Also

Description

• 

Let M be a manifold and let be a symmetric linear connection on the tangent bundle of M. If C is a curve in M with tangent vector T, then the geodesic equations for C with respect to the connection  is the system of second order ODEs defined by TT=0.

• 

The procedure GeodesicEquations(C, Gamma, t) returns the vector TT.

• 

This command is part of the DifferentialGeometry:-Tensor package, and so can be used in the form GeodesicEquations(...) only after executing the command with(DifferentialGeometry) and with(Tensor) in that order.  It can always be used in the long form DifferentialGeometry:-Tensor:-GeodesicEquations.

Examples

withDifferentialGeometry:withTensor:

 

Example 1.

First create a 2-dimensional manifold M and define a connection on the tangent space of M.

DGsetupx,y,M

frame name: M

(2.1)
M > 

ΓConnectionaD_x &t dx &t dy+D_x &t dy &t dx+byD_x &t dy &t dy

Γ:=aD_xdxdy+aD_xdydx+byD_xdydy

(2.2)

 

To determine the geodesic equations for this connection we first define a curve on M by specifying a list of functions of a single variable t.

M > 

Cxt,yt

C:=xt,yt

(2.3)

 

The program GeodesicEquations returns a vector whose components are the components of the geodesic equations.

M > 

VGeodesicEquationsC,Γ,t

V:=ⅆⅆtyt2byt+2ⅆⅆtxtⅆⅆtyta+ⅆⅆtⅆⅆtxtD_x+ⅆⅆtⅆⅆtytD_y

(2.4)

 

To solve these geodesic equations use DGinfo to obtain the coefficients of V as a list. Pass the result to dsolve to solve this system of 2 second order ODEs. See also DGsolve.

M > 

DETools:-DGinfoV,CoefficientSet

DE:=ⅆⅆtyt2byt+2ⅆⅆtxtⅆⅆtyta+ⅆ2ⅆt2xt,ⅆ2ⅆt2yt

(2.5)
M > 

simplifydsolveDE,explicit

xt=142b_C32a_C4tb_C32t+b_C33at2+2ⅇ2a_C3t+_C4a_C14_C2_C3a2_C3a2,yt=_C3t+_C4

(2.6)

See Also

DifferentialGeometry, Tensor, Christoffel, Connection, CovariantDerivative, DGinfo, DirectionalCovariantDerivative, ParallelTransportEquations


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