On $k$-diametral point configurations in Minkowski spaces

Universality theorems for linkages in the Minkowski plane

A mechanical linkage is a mechanism made of rigid rods linked together by flexible joints, in which some vertices are fixed and others may move. The partial configuration space of a linkage is the set of all the possible positions of a subset of the vertices. We characterize the possible partial configuration spaces of linkages in the Minkowski plane. We also give a proof of a differential universality theorem in the Minkowski plane: for any manifold M which is the interior of a compact manifold with boundary, there is a linkage which has a configuration space diffeomorphic to the disjoint uni…

Geometry of simplices in Minkowski spaces

There are many problems and configurations in Euclidean geometry that were never extended to the framework of (normed or) finite dimensional real Banach spaces, although their original versions are inspiring for this type of generalization, and the analogous definitions for normed spaces represent a promising topic. An example is the geometry of simplices in non-Euclidean normed spaces. We present new generalizations of well known properties of Euclidean simplices. These results refer to analogues of circumcenters, Euler lines, and Feuerbach spheres of simplices in normed spaces. Using duality…

Colorful simplicial depth, Minkowski sums, and generalized Gale transforms

The colorful simplicial depth of a collection of d+1 finite sets of points in Euclidean d-space is the number of choices of a point from each set such that the origin is contained in their convex hull. We use methods from combinatorial topology to prove a tight upper bound on the colorful simplicial depth. This implies a conjecture of Deza et al. (2006). Furthermore, we introduce colorful Gale transforms as a bridge between colorful configurations and Minkowski sums. Our colorful upper bound then yields a tight upper bound on the number of totally mixed facets of certain Minkowski sums of simp…

Universality theorems for linkages in homogeneous surfaces

A mechanical linkage is a mechanism made of rigid rods linked together by flexible joints, in which some vertices are fixed and others may move. The partial configuration space of a linkage is the set of all the possible positions of a subset of the vertices. We characterize the possible partial configuration spaces of linkages in the (Lorentz-)Minkowski plane, in the hyperbolic plane and in the sphere. We also give a proof of a differential universality theorem in the Minkowski plane and in the hyperbolic plane: for any compact manifold M, there is a linkage whose configuration space is diffe…

阿蒂亚的闵可夫斯基空间猜想对所有n≥3均不成立

Atiyah's Minkowski Space Conjecture Fails for Every $n\ge3$

该研究证明阿蒂亚的闵可夫斯基空间线性无关猜想对所有n≥3不成立，通过n=3的显式反例及零平移构造得到所有n>3的反例，明确n=2时该猜想成立。

Closed-Form Minkowski Sums of Convex Bodies with Smooth Positively Curved Boundaries

This article derives closed-form parametric formulas for the Minkowski sums of convex bodies in d-dimensional Euclidean space with boundaries that are smooth and have all positive sectional curvatures at every point. Under these conditions, there is a unique relationship between the position of each boundary point and the surface normal. The main results are presented as two theorems. The first theorem directly parameterizes the Minkowski sums using the unit normal vector at each surface point. Although simple to express mathematically, such a parameterization is not always practical to obtain…