PairSymmetrize

• PairSymmetrize[expr, {{i1,j1}, ..., {in,jn}}] symmetrizes expr with respect to exchange of both indices among any two pairs, i. e., under simultaneous change of i3<->i7 and of j3<->j7. By convention there is a factor 1/n! multiplying.

• This function is just a specialization of ImposeSymmetry for the pair-symmetric group corresponding to the given indices.
• See: Section 7.3.
• See also: Symmetrize, Antisymmetrize, PairAntisymmetrize.
• New in version 0.
• Last update: 28-X-2007 for version 0.9.3 of xTensor`.

Created by Mathematica  (May 16, 2008)