Unlabeled Structures

The main aim of this book is an introduction to the theory of classification, enumeration, construction and generation of unlabeled structures which means equivalence classes of labeled structures. A typical example is formed by incidence structures, where the names of the points (the labels) do not really matter, and so two incidence structures that differ only by a renumbering of the points are considered as essentially the same, as equivalent or as isomorphic. Prominent examples are unlabeled graphs, isometry classes of linear codes, isomorphism classes of designs, equivalence classes of switching functions, physical states and chemical isomers. We shall discuss these cases in detail.