SignPartition( pi )
returns the sign of a permutation with cycle structure pi.
gap> SignPartition([6,5,4,3,2,1]); -1
This function actually describes a homomorphism of the symmetric group S_n into the cyclic group of order 2, whose kernel is exactly the alternating group A_n (see SignPerm). Partitions of sign 1 are called even partitions while partitions of sign -1 are called odd.
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