\wrThe \wr symbol is used to denote the wreath product in group theory, which is a specialized product of two groups. It is often used in the context of permutation groups and is a way to construct new groups from known ones.
Wreath product of groups G and H
G \wr HWreath product of the symmetric group S_n with the cyclic group of order 2
S_n \wr \mathbb{Z}_2Iterated wreath product of the cyclic group of order 3
(\mathbb{Z}_3 \wr \mathbb{Z}_3) \wr \mathbb{Z}_3