The paper analyzes the parameterized complexity of evaluating Ontology Mediated Queries (OMQs) based on Guarded TGDs (GTGDs) and Unions of Conjunctive Queries (UCQs), in the setting where relational symbols might have unbounded arity and where the parameter is the size of the OMQ. It establishes exact criteria for fixed-parameter tractability (fpt) evaluation of recursively enumerable classes of such OMQs (under the widely held Exponential Time Hypothesis). One of the main technical tools introduced in the paper is an fpt-reduction from deciding parameterized uniform CSPs to parameterized OMQ evaluation. A fundamental feature of the reduction is preservation of measures which are known to be essential for classifying classes of parameterized uniform CSPs: submodular width (according to the well known result of Marx for unbounded-arity schemas) and treewidth (according to the well known result of Grohe for bounded-arity schemas). As such, the reduction can be employed to obtain hardness results for evaluation of classes of parameterized OMQs both in the unbounded and in the bounded arity case. Previously, in the case of bounded arity schemas, this has been tackled using a technique requiring full introspection into the construction employed by Grohe.

中文翻译：

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受保护的TGD下查询评估的效率：无限制Arity案例

本文分析了在关系符号可能具有无穷大且参数是OMQ大小的情况下，基于保护TGD（GTGD）和联合查询（UCQs）评估本体中介查询（OMQ）的参数化复杂性。 。它为此类OMQ的递归可枚举类的固定参数可扩展性（fpt）评估（在广泛使用的指数时间假设下）建立了精确的标准。本文介绍的主要技术工具之一是从确定参数化统一CSP到参数化OMQ评估的fpt缩减。减少的基本特征是保留了一些措施，这些措施对于分类参数化统一CSP的类别是必不可少的：次模块宽度（根据Marx对于无边界模式的公知结果）和树宽（根据Grohe对于边界的模式的公知结果）。这样，在无边界和有边界的情况下，可以使用减少来获得硬度结果，以评估参数化OMQ的类别。以前，在有限制的框架模式的情况下，已使用需要对Grohe所采用的构造进行全面自省的技术来解决此问题。