Constrains ExprX to be greater than ExprY. Also constrains all variables appearing in ExprX and ExprY to be domain variables and checks that all constants and ground sub-expressions are integers.
ConsistencyModule is the optional module specification to give the consistency level for the propagation for this constraint: gfd_bc for bounds consistency, and gfd_gac for domain (generalised arc) consistency. Note that some operators (integer division, modulus) only support bounds consistency and will be propagated with bounds consistency even when posted with gfd_gac.
This constraint is implemented using Gecode's MiniModel's rel() for both integer and boolean expressions, with sub-expressions/constraints not supported by MiniModel factored out and posted as auxiliary constraints.
A more restricted version of this constraint is defined in the global constraint catalog as 'gt'. Here the constraint is defined between two domain variables rather than two expressions.