3 papers
math.MG2025
Second-order prestress stability and third-order rigidity of polyhedral surfaces
Zeyuan He, Daniel Robertz
There has been a longstanding confusion on the proper definition of higher order rigidity and flexibility in geometric constraint systems. Recently, an energy-based formulation of…
gr-qc2024
Coordinate- and spacetime-independent quantum physics
V. A. Emelyanov, D. Robertz
The concept of a particle is ambiguous in quantum field theory. It is generally agreed that particles depend not only on spacetime, but also on coordinates used to parametrise spac…
math.CO2024
Construction of Toroidal Polyhedra corresponding to perfect Chains of wild Tetrahedra
Reymond Akpanya, Vanishree Krishna Kirekod, Alice C. Niemeyer +1
In 1957, Steinhaus proved that a chain of regular tetrahedra, meeting face-to-face and forming a closed loop does not exist. Over the years, various modifications of this statement…