Recognizability, hypergraph operations, and logical types

摘要: We study several algebras of graphs and hypergraphs the corresponding notions equational sets recognizable sets. generalize unify existing results which compare associated The basic algebra on relational structures is based disjoint union quantifier-free definable operations. expand it to an equivalent one by adding operations with ''few quantifiers'', i.e., that take into account local information about elements or tuples. also consider monadic second-order transductions we prove inverse image a set under such transduction recognizable.