The Z User Group (ZUG) was established in 1992 to promote use and development of the Z notation, a formal specification language for the description of and reasoning about computer-based systems.
[7] ZUG has organised a series of Z User Meetings approximately every 18 months initially.
In 2010, the ABZ Conference also includes Alloy, a Z-like specification language with associated tool support.
[10] The Z User Group participated at the FM'99 World Congress on Formal Methods in Toulouse, France, in 1999.
[12] The following proceedings were produced by the Z User Group:[13][14] The following ZB conference proceedings were jointly produced with the Association de Pilotage des Conférences B (APCB), covering the Z notation and the related B-Method:[13] From 2008, the ZB conferences were expanded to be the ABZ conference, also including abstract state machines.