Let G be the set of finite graphs whose vertices belong to some fixed countable set, and let ≡ be an equivalence relation on G. By the strengthening of ≡ we mean an equivalen...
A class of relational structures is said to have the extension preservation property if every first-order sentence that is preserved under extensions on the class is equivalent t...
Abstract. We give the first mechanized proof of the fact that for showing termination of a term rewrite system, we may restrict to well-formed terms using just the function symbols...
In this paper we discuss the question which properties of a formally verified component are preserved when the component is changed due to an adaption to a new use. More specific...
Unions of conjunctive queries, also known as select-project-join-union queries, are the most frequently asked queries in relational database systems. These queries are definable b...