Please note: In order to keep Hive up to date and provide users with the best features, we are no longer able to fully support Internet Explorer. The site is still available to you, however some sections of the site may appear broken. We would encourage you to move to a more modern browser like Firefox, Edge or Chrome in order to experience the site fully.

Topological Invariants for Projection Method Patterns, Paperback / softback Book

Topological Invariants for Projection Method Patterns Paperback / softback

Part of the Memoirs of the American Mathematical Society series

Paperback / softback

Description

This memoir develops, discusses and compares a range of commutative and non-commutative invariants defined for projection method tilings and point patterns.

The projection method refers to patterns, particularly the quasiperiodic patterns, constructed by the projection of a strip of a high dimensional integer lattice to a smaller dimensional Euclidean space.

In the first half of the memoir the acceptance domain is very general - any compact set which is the closure of its interior - while in the second half we concentrate on the so-called canonical patterns.

The topological invariants used are various forms of $K$-theory and cohomology applied to a variety of both $C^*$-algebras and dynamical systems derived from such a pattern.The invariants considered all aim to capture geometric properties of the original patterns, such as quasiperiodicity or self-similarity, but one of the main motivations is also to provide an accessible approach to the the $K_0$ group of the algebra of observables associated to a quasicrystal with atoms arranged on such a pattern.

The main results provide complete descriptions of the (unordered) $K$-theory and cohomology of codimension 1 projection patterns, formulae for these invariants for codimension 2 and 3 canonical projection patterns, general methods for higher codimension patterns and a closed formula for the Euler characteristic of arbitrary canonical projection patterns.Computations are made for the Ammann-Kramer tiling.

Also included are qualitative descriptions of these invariants for generic canonical projection patterns.

Further results include an obstruction to a tiling arising as a substitution and an obstruction to a substitution pattern arising as a projection.

One corollary is that, generically, projection patterns cannot be derived via substitution systems.

Information

Other Formats

Information