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We study abstractions within an extension of UCQs with a limited form of inequality and a special predicate marking database constants. While this extension does not lead to an increased complexity of the problems of interest, it is able to express minimally complete abstractions, hence perfect abstractions when they exist. We also characterize maximally sound abstractions by making a new connection with the notion of maximum recovery stemming from data exchange.
From: Marie-Laure Mugnier [view email]
[v1]
Tue, 23 Jun 2026 14:17:08 UTC (57 KB)
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