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Tensor perturbations are represented by Laplacian eigenfunctions

| |
(24) |

which satisfy a transverse-traceless condition
| |
(25) |

that forbids the construction of scalar and vector objects
such as density and velocity fields. The modes take on
an explicit representation of
| |
(26) |

Notice that
and thus tensors stimulate the
modes in the radiation.
In the following sections, we often only explicitly show
the positive *m* value with the understanding that its opposite
takes on the same form except where otherwise noted (i.e. in
the *B*-type polarization where a sign reversal occurs).

*Wayne Hu*

*9/9/1997*