Ultraprecise bearings that allow a rocking motion make use of knife-edges or pivots. As the bearing rocks, it rolls, translating sideways by a distance that depends on the radius of contact. The further it rolls, the less precise is its positioning, so the smaller the radius of contact \(R\) the better. But the smaller the radius of contact, the greater is the contact pressure \((F / A)\). If this exceeds the hardness \(H\) of either face of the bearing, it will be damaged. Elastic deformation is bad too: it flattens the contact, increasing the contact area and the roll. Translate the requirements for the bearing, listing function, constraints, objective and free variable.