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quaternion-valued differential forms

asked 10 years ago

SL gravatar image

updated 10 years ago

I'm trying to define quaternion-valued differential forms in Sage. For example, take e0, e1, e2, e3 to be the quaternion generators and dx0, dx1, dx2, dx3 be the generators of the exterior algebra. So for example I'd like to be able to compute dXdX, where dX=e0dx0+e1dx1+e2dx2+e3dx3, dX=e0dx0e1dx1e2dx2e3dx3.

Edit: I tried taking a tensor product between an exterior algebra and a quaternion algebra

sage: ext_alg.<x0,x1,x2,x3> = ExteriorAlgebra(QQ)
sage: ext_alg in Algebras(QQ)
True
sage: quat_alg = QuaternionAlgebra(QQ,-1,-1)
sage: quat_alg in Algebras(QQ)
True
sage: tensor((ext_alg, quat_alg))  # this doesn't work!
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answered 10 years ago

SL gravatar image

updated 10 years ago

This seems to work fine:

sage: quat_alg = QuaternionAlgebra(QQ,-1,-1)
sage: ext_alg.<x0,x1,x2,x3> = ExteriorAlgebra(quat_alg)
sage: x = x0+x1*i+x2*j+x3*k
sage: x_dag = x0-x1*i-x2*j-x3*k
# now some computations
sage: x*x_dag
-2*i*x0^x1 - 2*j*x0^x2 - 2*k*x0^x3 - 2*k*x1^x2 + 2*j*x1^x3 - 2*i*x2^x3
sage: x*x_dag*x
-6*k*x0^x1^x2 + 6*j*x0^x1^x3 - 6*i*x0^x2^x3 + 6*x1^x2^x3
sage: x*x_dag*x*x_dag
-24*x0^x1^x2^x3
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Asked: 10 years ago

Seen: 367 times

Last updated: Mar 01 '15