DifferentialGeometry[DGconjugate] - find the complex conjugate of a vector, tensor or differential form; find the conjugate of a quaternion or octonion
DifferentialGeometry[DGRe] - find the real part of a vector, tensor or differential form; find the real part of a quaternion or octonion
DifferentialGeometry[DGIm] - find the imaginary part of a vector, a tensor or differential form; find the imaginary part of a quaternion or octonion
Calling Sequence
Parameters
Description
Examples
DGconjugate(T, option)
DGconjugate(X)
DGRe(T, option)
DGRe(X)
DGIm(T, option)
DGIm(X)
T
-
a tensor, differential form or vector defined on a manifold with complex coordinates
X
a quaternion or octonion
option
the keyword argument complexconjugatepairs = [[a1, a2], [b1, b2], ...] where [a1, a2], ... are Maple expressions (appearing the coefficients of T) which are to be interchanged under conjugation
The calling sequences DGconjugate(T, option), DGRe(T, option), DGIm(T, option) compute the complex conjugate, real part, and imaginary part of a tensor or differential form T. The coordinate variables are assumed to be real unless explicitly declared to be complex by using the keyword argument complexconjugatepairs as part of the calling sequence to DGsetup.
The calling sequences DGconjugate(X), DGRe(X), DGIm(X) compute the complex conjugate, real part, and imaginary part of a quaternion or octonion X.
with⁡DifferentialGeometry:with⁡LieAlgebras:
Example 1.
Define a 4-dimensional manifold with coordinates x, y, u, v, where x and y are real coordinates, u and v are complex coordinates and the complex conjugate of u is v.
DGsetup⁡x,y,u,v,M,complexconjugatepairs=u,v
frame name: M
Calculate the complex conjugate of some vectors on M.
X1≔evalDG⁡D_x+D_u
X1:=D_x+D_u
DGconjugate⁡X1
D_x+D_v
X2≔evalDG⁡I⁢D_x+D_u−D_v
X2:=I⁢D_x+D_u−D_v
DGconjugate⁡X2
−I⁢D_x−D_u+D_v
Calculate the complex conjugate of a vector depending upon parameters α and β. First assume α and β are real.
X3≔evalDG⁡α⁢D_x+uβ⁢D_v
X3:=α⁢D_x+u⁢D_vβ
DGconjugate⁡X3
α⁢D_x+v⁢D_uβ
Now suppose that α is complex and that the complex conjugate of α is β.
DGconjugate⁡X3,complexconjugatepairs=α,β
β⁢D_x+v⁢D_uα
Calculate the complex conjugate of a rank 2 tensor:
T1≔evalDG⁡u⁢dx&tdy+y⁢dx&tdv+u2+v2⁢du&tdv
T1:=u⁢dx⁢dy+y⁢dx⁢dv+u2+v2⁢du⁢dv
DGconjugate⁡T1
v⁢dx⁢dy+y⁢dx⁢du+u2+v2⁢dv⁢du
Calculate the complex conjugate of a rank 4 differential form
ω1≔evalDG⁡I⁢dx&wdy&wdu&wdv
ω1:=I⁢dx⁢⋀⁢dy⁢⋀⁢du⁢⋀⁢dv
DGconjugate⁡ω1
I⁢dx⁢⋀⁢dy⁢⋀⁢du⁢⋀⁢dv
Example 2.
Calculate the real and imaginary parts of the vectors, tensors and differential forms defined in Example 1.
X1,DGRe⁡X1,DGIm⁡X1
D_x+D_u,D_x+12⁢D_u+12⁢D_v,−12⁢I⁢D_u+12⁢I⁢D_v
X2,DGRe⁡X2,DGIm⁡X2
I⁢D_x+D_u−D_v,0⁢D_x,D_x−I⁢D_u+I⁢D_v
T1
u⁢dx⁢dy+y⁢dx⁢dv+u2+v2⁢du⁢dv
DGRe⁡T1
12⁢v+12⁢u⁢dx⁢dy+12⁢y⁢dx⁢du+12⁢y⁢dx⁢dv+12⁢u2+12⁢v2⁢du⁢dv+12⁢u2+12⁢v2⁢dv⁢du
DGIm⁡T1
−12⁢I⁢−v+u⁢dx⁢dy+12⁢I⁢y⁢dx⁢du−12⁢I⁢y⁢dx⁢dv−12⁢I⁢u2+v2⁢du⁢dv+12⁢I⁢u2+v2⁢dv⁢du
ω1,DGRe⁡ω1,DGIm⁡ω1
I⁢dx⁢⋀⁢dy⁢⋀⁢du⁢⋀⁢dv,I⁢dx⁢⋀⁢dy⁢⋀⁢du⁢⋀⁢dv,0⁢dx⁢⋀⁢dy⁢⋀⁢du⁢⋀⁢dv
Example 3.
The command DGconjugate works with anholonomic frames. To check this, first define an anholonomic frame and initialize it..
FD≔FrameData⁡D_x,u⁢D_y,u⁢D_u+v⁢D_v,v⁢D_u−u⁢D_v,N
FD:=E2,E3=−E2,E2,E4=−v⁢E2u
DGsetup⁡FD
frame name: N
DGconjugate⁡E1,E2,E3,E4
E1,v⁢E2u,E3,−E4
Example 4.
Find the conjugate of a quaternion. First use the command AlgebraData to obtain the structure equations for the quaternions.
AD≔AlgebraLibraryData⁡Quaternions,alg
AD:=e12=e1,e1.e2=e2,e1.e3=e3,e1.e4=e4,e2.e1=e2,e22=−e1,e2.e3=e4,e2.e4=−e3,e3.e1=e3,e3.e2=−e4,e32=−e1,e3.e4=e2,e4.e1=e4,e4.e2=e3,e4.e3=−e2,e42=−e1
The labels for the vectors and dual 1-forms can be specified upon initialization of the algebra. We will use the standard e,i,j,k for the quaternion basis vectors, and α,β,δ,ε for the dual 1-forms.
DGsetup⁡AD,e,i,j,k,α,β,δ,ε
algebra name: alg
MultiplicationTable⁡
Define a quaternion.
X≔evalDG⁡3⁢e+2⁢i−3⁢j+4⁢k
X:=3⁢e+2⁢i−3⁢j+4⁢k
DGconjugate⁡X
3⁢e−2⁢i+3⁢j−4⁢k
Example 5.
Find the conjugate of an octonian. Use the command AlgebraData to obtain the structure equations for the octonions.
AD≔AlgebraLibraryData⁡Octonions,alg
AD:=e12=e1,e1.e2=e2,e1.e3=e3,e1.e4=e4,e1.e5=e5,e1.e6=e6,e1.e7=e7,e1.e8=e8,e2.e1=e2,e22=−e1,e2.e3=e4,e2.e4=−e3,e2.e5=e6,e2.e6=−e5,e2.e7=−e8,e2.e8=e7,e3.e1=e3,e3.e2=−e4,e32=−e1,e3.e4=e2,e3.e5=e7,e3.e6=e8,e3.e7=−e5,e3.e8=−e6,e4.e1=e4,e4.e2=e3,e4.e3=−e2,e42=−e1,e4.e5=e8,e4.e6=−e7,e4.e7=e6,e4.e8=−e5,e5.e1=e5,e5.e2=−e6,e5.e3=−e7,e5.e4=−e8,e52=−e1,e5.e6=e2,e5.e7=e3,e5.e8=e4,e6.e1=e6,e6.e2=e5,e6.e3=−e8,e6.e4=e7,e6.e5=−e2,e62=−e1,e6.e7=−e4,e6.e8=e3,e7.e1=e7,e7.e2=e8,e7.e3=e5,e7.e4=−e6,e7.e5=−e3,e7.e6=e4,e72=−e1,e7.e8=−e2,e8.e1=e8,e8.e2=−e7,e8.e3=e6,e8.e4=e5,e8.e5=−e4,e8.e6=−e3,e8.e7=e2,e82=−e1
DGsetup⁡AD
Define an octonion.
X≔evalDG⁡3⁢e1+2⁢e3−3⁢e6+4⁢e8
X:=3⁢e1+2⁢e3−3⁢e6+4⁢e8
3⁢e1−2⁢e3+3⁢e6−4⁢e8
See Also
DifferentialGeometry
LieAlgebras
AlgebraData
AlgebraInverse
AlgebraNorm
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