On the Monadic Second-Order Transduction Hierarchy

We compare classes of finite relational structures via monadic second-order transductions. More precisely, we study the preorder where we set C \subseteq K if, and only if, there exists a transduction {\tau} such that C\subseteq{\tau}(K). If we only consider classes of incidence structures we can co...

Full description

Bibliographic Details
Main Authors: Achim Blumensath, Bruno Courcelle
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2010-06-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/1208/pdf
Description
Summary:We compare classes of finite relational structures via monadic second-order transductions. More precisely, we study the preorder where we set C \subseteq K if, and only if, there exists a transduction {\tau} such that C\subseteq{\tau}(K). If we only consider classes of incidence structures we can completely describe the resulting hierarchy. It is linear of order type {\omega}+3. Each level can be characterised in terms of a suitable variant of tree-width. Canonical representatives of the various levels are: the class of all trees of height n, for each n \in N, of all paths, of all trees, and of all grids.
ISSN:1860-5974