On affine motions and bar frameworks in general position

A. Y. Alfakih; Yinyu Ye

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arXiv · 1009.3318

On affine motions and bar frameworks in general position

A. Y. Alfakih·Yinyu Ye

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Abstract

A configuration p in r-dimensional Euclidean space is a finite collection of points (p^1,...,p^n) that affinely span R^r. A bar framework, denoted by G(p), in R^r is a simple graph G on n vertices together with a configuration p in R^r. A given bar framework G(p) is said to be universally rigid if there does not exist another configuration q in any Euclidean space, not obtained from p by a rigid motion, such that ||q^i-q^j||=||p^i-p^j|| for each edge (i,j) of G. It is known that if configuration p is generic and bar framework G(p) in R^r admits a positive semidefinite stress matrix S of rank n-r-1, then G(p) is universally rigid. Connelly asked whether the same result holds true if the genericity assumption of p is replaced by the weather assumption of general position. We answer this question in the affirmative in this paper.

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A. Y. Alfakih, Yinyu Ye. 2010-09-17. On affine motions and bar frameworks in general position. https://arxiv.org/abs/1009.3318

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