This workshop is motivated by a growing interest, originating in several applied fields, towards studying algorithmic aspects of geometric structures with periodicity and symmetry, in static, dynamic and kinetic settings.

Point sets and graphs under the action of crystallographic groups in various geometries have traditionally been studied within the framework of mathematical crystallography. Periodic boundary conditions for moving particles are a de facto standard in physical simulations. In materials science, deformations of crystalline materials that maintain symmetry and periodicity are investigated. In all these settings, new mathematical and algorithmic techniques are required for efficiently carrying out the calculations and the simulations.

One of the goals of this workshop is to bring to the attention of the larger computational geometry community a range of problems in periodic and symmetric settings, such as but not limited to the study of Delaunay tesselations and Voronoi diagrams, bar-and-joint frameworks, polyhedral surfaces, foams, and applications that have emerged in other fields.
Another goal is to bring in people from other disciplines who are potential users of algorithms and software developed to address these questions.

This workshop is particularly timely, since 2014 is the International Year of Crystallography


Ileana Streinu and Monique Teillaud


Sunday, June 8: 14:30-16:00 and 16:30-18:00
Monday, June 9: 15:00-16:20 and 16:40-18:00

Tentative Program

Sunday 8
14:30-14:35 Welcome - slides
14:35-14:55 Boris Thibert Embeddings of the square flat torus and smooth fractals - slides
14:55-15:20 Monique Teillaud Voronoi diagrams and Bolza surface - slides
15:20-16:00 Benjamin Burton Exact computation with hyperbolic 3-manifolds - slides
16:00-16:30 Coffee Break
16:30-17:10 Hiro Tanaka Coordinated motions of repetitive structures from a mechanical point of view - slides
17:10-17:30 Luca Castelli Aleardi, Olivier Devillers, and Éric Fusy Crossing-free straight-line drawing of graphs on the flat torus - slides
17:30-17:50 Norie Fu and Vorapong Suppakitpaisarn The Betweenness Centrality on 1-Dimensional Periodic Graphs - slides
Monday 9
15:00-15:40 Ciprian Borcea A Geometric Theory of Auxetic Deformations - slides
15:40-16:00 Louis Theran Ultrarigid periodic frameworks - slides
16:00-16:20 Bernd Schulze and Shin-ichi Tanigawa Linking Rigid Bodies Symmetrically - slides
16:20-16:40 Coffee Break
16:40-17:20 George Phillips Dynamics of protein molecules in crystals: "Please hold still so we can take your picture" - slides
17:20-17:40 Helmut Alt for Claudia Dieckmann Approximate Symmetries of Point Patterns - slides
17:40-18:00 Jack Snoeyink, Auston Sterling, and Vishal Verma Symmetry-aware placement of hydrogens in molecules: Reduce and cctbx - slides


The abstracts and slides of talks presented at the workshop will be made available on the workshop website.

In consultation with the speakers, we will consider the possibility of a special issue devoted to the topics of the workshop.

[closed] Call for talks

A talk proposal consists in a short abstract (1 page long), formatted according to the following style file (adapted from the style for the YRF, thanks to Maarten Löffler). See
Proposals must be sent by email to the organizers.

Important dates (23:59 Honolulu time):
- April 10, 2014: Deadline for talk proposals
- April 30, 2014: Notification of acceptance