 Integrity constraints represent extra conditions that should follow from the merged bases. The interest of integrity constraints is to ensure that the aggregation of individual pieces of information satisfies some problem-specific requirement. For example, suppose that members of a city council have to decide what to build in a certain area. We can have constraints on the available budget (enough to cover only some of the projects) but also constraints on the coexistence of different projects (we may not build a parking lot and a playground in that area, but we may build a playground and a public library). If the (possibly empty) set of integrity constraints is denoted by the belief base IC, \(\Delta_{\IC}(E)\) denotes the result of merging the multi-set E of belief bases given IC. Intuitively, the result will be a consistent belief base representing the collective beliefs and implying IC.