Ref: http://arxiv.org/abs/0711.3220
Fourvector algebra
Author: Diego Saa (Submitted on 20 Nov 2007)
Abstract: The algebra of fourvectors is described. The fourvectors are more appropriate than the Hamilton quaternions for its use in Physics and the sciences in general. The fourvectors embrace the 3D vectors in a natural form. It is shown the excellent ability to perform rotations with the use of fourvectors, as well as their use in relativity for producing Lorentz boosts, which are understood as simple rotations.
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(1) -> _*_*(x,y)==concat(x(1) * y(1) + dot(x(2..), y(2..)), x(1) * y(2..) - x(2..) * y(1) + cross(x(2..), y(2..)))
Type: Void
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e:Vector INT:=[1,0,0,0]
Type: Vector(Integer)
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i:Vector INT:=[0,1,0,0]
Type: Vector(Integer)
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j:Vector INT:=[0,0,1,0]
Type: Vector(Integer)
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k:Vector INT:=[0,0,0,1]
Type: Vector(Integer)
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test(e**e=e) and _
test(i**i=e) and _
test(j**j=e) and _
test(k**k=e) and _
test(e**i=i) and _
test(e**j=j) and _
test(e**k=k) and _
test(i**e=-i) and _
test(j**e=-j) and _
test(k**e=-k) and _
test(i**j=k) and _
test(j**i=-k) and _
test(k**i=j) and _
test(i**k=-j) and _
test(j**k=i) and _
test(k**j=-i)
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Compiling function ** with type (Vector(Integer), Vector(Integer))
-> Vector(Integer)
Type: Boolean
Axiom has a domain for NonAssociative? Algebra
This is documented in the article:
Computations in Algebras of Fixed Rank by Johannes Grabmeir and Robert Wisbauer, from the book "Computational Algebra"
By Klaus G. Fischer, Philippe Loustaunau, Jay Shapiro.
The algebra above can be given by structural constants.
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)clear all
All user variables and function definitions have been cleared.
sc:Vector Matrix Fraction Integer := [ _
[[ 1, 0, 0, 0], _
[ 0, 1, 0, 0], _
[ 0, 0, 1, 0], _
[ 0, 0, 0, 1]], _
[[ 0, 1, 0, 0], _
[-1, 0, 0, 0], _
[ 0, 0, 0, 1], _
[ 0, 0,-1, 0]], _
[[ 0, 0, 1, 0], _
[ 0, 0, 0,-1], _
[-1, 0, 0, 0], _
[ 0, 1, 0, 0]], _
[[ 0, 0, 0, 1], _
[ 0, 0, 1, 0], _
[ 0,-1, 0, 0], _
[-1, 0, 0, 0]]];
Type: Vector(Matrix(Fraction(Integer)))
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V:=AlgebraGivenByStructuralConstants(Fraction Integer, 4, [e,i,j,k],sc)
Type: Type
Multiplication
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a:=basis()$V
Type: Vector(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]))
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matrix([[(a.i * a.j) for j in 1..4] for i in 1..4])$OutputForm
Commutator and Associator
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matrix([[commutator(a.x,a.y) for x in 1..4] for y in 1..4])$OutputForm
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[matrix([[associator(a.x,a.y,a.z) for x in 1..4] for y in 1..4])$OutputForm for z in 1..4]
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for x in 1..4 repeat
for y in 1..4 repeat
for z in 1..4 repeat
if associator(a.x,a.y,a.z) ~= 0$V then
output([[a.x,a.y,a.z],"=",associator(a.x,a.y,a.z)])
[[i, e, e], "=", 2 i]
[[i, e, i], "=", - 2 e]
[[i, e, j], "=", - 2 k]
[[i, e, k], "=", 2 j]
[[i, i, e], "=", 2 e]
[[i, i, i], "=", 2 i]
[[i, i, j], "=", 2 j]
[[i, i, k], "=", 2 k]
[[j, e, e], "=", 2 j]
[[j, e, i], "=", 2 k]
[[j, e, j], "=", - 2 e]
[[j, e, k], "=", - 2 i]
[[j, j, e], "=", 2 e]
[[j, j, i], "=", 2 i]
[[j, j, j], "=", 2 j]
[[j, j, k], "=", 2 k]
[[k, e, e], "=", 2 k]
[[k, e, i], "=", - 2 j]
[[k, e, j], "=", 2 i]
[[k, e, k], "=", - 2 e]
[[k, k, e], "=", 2 e]
[[k, k, i], "=", 2 i]
[[k, k, j], "=", 2 j]
[[k, k, k], "=", 2 k]
Type: Void
Volume form?
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a.2 * (a.3 * a.4) = (a.2 * a.3) * a.4
Type: Equation(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]))
Check standard properties
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leftUnit()$V
Type: Union(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]),
...)
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rightUnit()$V
Type: Union("failed",...)
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alternative?()$V
Type: Boolean
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leftAlternative?()$V
Type: Boolean
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rightAlternative?()$V
Type: Boolean
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associative?()$V
Type: Boolean
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antiAssociative?()$V
Type: Boolean
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--powerAssociative?()$V
commutative?()$V
Type: Boolean
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antiCommutative?()$V
Type: Boolean
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jordanAlgebra?()$V
Type: Boolean
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jordanAdmissible?()$V
Type: Boolean
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noncommutativeJordanAlgebra?()$V
Type: Boolean
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lieAlgebra?()$V
Type: Boolean
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lieAdmissible?()$V
Type: Boolean
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jacobiIdentity?()$V
Type: Boolean
Commuting elements
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V has FramedNonAssociativeAlgebra(Fraction Integer)
Type: Boolean
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basisOfCommutingElements()$AlgebraPackage(Fraction Integer,V)
Type: List(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]))
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basisOfCenter()$AlgebraPackage(Fraction Integer,V)
Type: List(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]))
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basisOfCentroid()$AlgebraPackage(Fraction Integer,V)
Type: List(Matrix(Fraction(Integer)))
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basisOfNucleus()$AlgebraPackage(Fraction Integer,V)
Type: List(AlgebraGivenByStructuralConstants
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]))
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basisOfLeftNucloid()$AlgebraPackage(Fraction Integer,V)
Type: List(Matrix(Fraction(Integer)))
Symbolic computations
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G:=GenericNonAssociativeAlgebra(Fraction Integer, 4, [e,i,j,k],sc)
Type: Type
Look for Idempotents
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conditionsForIdempotents()$G
Type: List(Polynomial(Fraction(Integer)))
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gb:=groebnerFactorize %
Type: List(List(Polynomial(Fraction(Integer))))
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associatorDependence()$G
Type: List(Vector(Fraction(Polynomial(Fraction(Integer)))))
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q:=leftRankPolynomial()$G
Type: SparseUnivariatePolynomial
?(Fraction(Polynomial(Fraction(Integer))))
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map(factor,coefficients q)
Type: List(Factored(Fraction(Polynomial(Fraction(Integer)))))
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rightUnit()$G
Type: Union("failed",...)
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p1:=generic([x1,y1,z1,w1])$G
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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p2:=generic([x2,y2,z2,w2])$G
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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p3:=generic([x3,y3,z3,w3])$G
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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leftRecip(p1)$G
Type: Union(GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]]),
...)
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rightRecip(p1)$G
Type: Union("failed",...)
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leftRegularRepresentation(p1)
Type: Matrix(Fraction(Polynomial(Fraction(Integer))))
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rightRegularRepresentation(p1)
Type: Matrix(Fraction(Polynomial(Fraction(Integer))))
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associator(p1,p2,p3)$G
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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associator(p1,p1,p2)
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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associator(p1,p2,p2)
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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p1*p1
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
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p1*p2 + p2*p1
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])
fricas
p1*(p1*p1)+(p1*p1)*p1
Type: GenericNonAssociativeAlgebra
?(Fraction(Integer),
4,
[e,
i,
j,
k],
[[[1,
0,
0,
0],
[0,
1,
0,
0],
[0,
0,
1,
0],
[0,
0,
0,
1]],
[[0,
1,
0,
0],
[-1,
0,
0,
0],
[0,
0,
0,
1],
[0,
0,
-1,
0]],
[[0,
0,
1,
0],
[0,
0,
0,
-1],
[-1,
0,
0,
0],
[0,
1,
0,
0]],
[[0,
0,
0,
1],
[0,
0,
1,
0],
[0,
-1,
0,
0],
[-1,
0,
0,
0]]])