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Preservation and decomposition theorems for bounded degree structures

Frederik Harwath ; Lucas Heimberg ; Nicole Schweikardt.
We provide elementary algorithms for two preservation theorems for first-order sentences (FO) on the class \^ad of all finite structures of degree at most d: For each FO-sentence that is preserved under extensions (homomorphisms) on \^ad, a \^ad-equivalent existential (existential-positive)&nbsp;[&hellip;]
Published on December 29, 2015

A note on the expressive power of linear orders

Thomas Schwentick ; Nicole Schweikardt.
This article shows that there exist two particular linear orders such that first-order logic with these two linear orders has the same expressive power as first-order logic with the Bit-predicate FO(Bit). As a corollary we obtain that there also exists a built-in permutation such that first-order&nbsp;[&hellip;]
Published on December 14, 2011

Enumerating Answers to First-Order Queries over Databases of Low Degree

Arnaud Durand ; Nicole Schweikardt ; Luc Segoufin.
A class of relational databases has low degree if for all $\delta>0$, all but finitely many databases in the class have degree at most $n^{\delta}$, where $n$ is the size of the database. Typical examples are databases of bounded degree or of degree bounded by $\log n$. It is known that over a&nbsp;[&hellip;]
Published on May 10, 2022

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