Combinatorical and Algebraic Structures Seminar
Session details
| Date: | 3.3.2020 |
| Speaker: | Jan Legerský, RISC, Johannes Kepler Universität & FIT, České vysoké učení technické v Praze |
| Title: | Rotationally symetric flexible frameworks |
| Abstract: | A framework $(G,p)$, which is a graph $G$ with a placement $p$ of its vertices into the plane, is called flexible if there are infinitely many non-congruent placements of $G$ having the same distances between adjacent vertices as in $p$. It has been shown that a graph admits a flexible framework if and only if it has a NAC-coloring - an edge coloring using two colors such that each cycle is either monochromatic or contains at least two red and two blue edges. In this talk, we require that the framework has an $n$-fold rotational symmetry: the existence of a flexible $n$-fold symmetric framework for a given graph can be characterized using NAC-colorings with some extra conditions imposed. |
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