It makes use of the #92;mathbb#123;Z#125;#95;k-action generated by a vertical 1#47;k-shift but can also be related, for prequantized balls, to the #92;mathbb#123;Z#125;#95;k-equivariant contact homology developed by Milin (2008) in her proof of orderability of lens spaces..
Source: wiktionary