Dr. techn. Ing. Jan Legerský


Paradoxical flexibility of frameworks

"LA granty"
Czech Science Foundation
2022 - 2025
A framework which is a graph together with a realization of its vertices in some space is called rigid if there are only finitely many realizations inducing the same edge lengths as the given one, up to isometries. Otherwise, the framework is flexible. Since rigidity is a generic property, the graph itself can be called rigid if every generic realization yields a rigid framework. Nevertheless, such a rigid graph can have non-generic flexible realizations. These paradoxical situations are investigated in the frame of this project. Using tools from algebraic geometry, the existence of paradoxical motions in the plane was recently characterized in terms of a special type of colorings of the edges. The purpose of this project is to combine graph theory and combinatorics with more sophisticated tools from algebraic geometry in order to be able to answer paradoxical flexibility questions in a broader sense. As such we are interested in symmetric flexes, different generalizations of rigidity, applications thereof to sensor networks and the above mentioned edge colorings.