No-slip rolling realization of the equidistant separating curve
Determine whether, for every connected bounded subset A of the Euclidean plane R^2 and every ε > 0, there exists a motion of a circle (wheel) of radius ε lying in the plane such that the circle continuously touches A without intersecting A, the center of the circle traces a simple closed curve that bounds the region containing A, and the motion occurs without slipping along the boundary of A throughout the trajectory.
References
However, we do not know whether it is always possible to ``roll'' that wheel without slipping.
— Separation of plane sets by equidistant simple closed curves
(2403.20166 - Volkov et al., 29 Mar 2024) in Introduction