TR-2014-04

Henneberg moves on mechanisms

Bill Jackson, Tibor Jordán, Brigitte Servatius, Herman Servatius

Published in:
Beitr Algebra Geom 56, 587–591 (2015). DOI link

A bar-and-joint framework in the plane with degree of freedom 1 is called a mechanism. It is well-known that the operations of 0-extension and 1-extension, the so called Henneberg moves, can always be performed on a framework so that its degree of freedom is preserved. It was conjectured by the first and second author in 2012 that for a mechanism in generic position these operations can be performed without restricting its motion. In this note we provide a counterexample.

Bibtex entry:

@techreport{egres-14-04,

AUTHOR	=	{Jackson, Bill and Jord{\'a}n, Tibor and Servatius, Brigitte and Servatius, Herman},
TITLE	=	{Henneberg moves on mechanisms},
NOTE	=	{{\tt egres.elte.hu}},
INSTITUTION	=	{Egerv{\'a}ry Research Group, Budapest},
YEAR	=	{2014},
NUMBER	=	{TR-2014-04}

}