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SciMax Toolbox >> nptetrad

nptetrad

Maxima Function

Calling Sequence

nptetrad ()

Description

Computes a Newman-Penrose null tetrad (np) and its raised-index counterpart (npi). See for an example.

The null tetrad is constructed on the assumption that a four-diemensional orthonormal frame metric with metric signature (-,+,+,+) is being used. The components of the null tetrad are related to the inverse frame matrix as follows:

np  = (fri  + fri ) / sqrt(2)
  1       1      2
np  = (fri  - fri ) / sqrt(2)
  2       1      2
np  = (fri  + %i fri ) / sqrt(2)
  3       3         4
np  = (fri  - %i fri ) / sqrt(2)
  4       3         4
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