is symmetric only in and , but either (nonzero)
or (nonzero) can be moved to the third position by using
19.21.7 |
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or the corresponding equation with and interchanged.
19.21.8 |
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19.21.9 |
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19.21.10 |
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Because is completely symmetric, can be permuted on the
right-hand side of (19.21.10) so that if the
variables are real, thereby avoiding cancellations when is
calculated from and (see §19.36(i)).
19.21.11 |
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where both summations extend over the three cyclic permutations of .
Connection formulas for are given in
Carlson (1977b, pp. 99, 101, and 123–124).