Some necessary metric conditions for flexibility of suspensions (Q1851537)

The author proposes one of the possible methods of compiling the equation for determining the diagonal length of a polyhedron of certain type, namely, a suspension. The left hand part of such an equation is a polynomial depending on the length of the suspension ribs (i.e. on its metric) and on the given diagonal. The senior coefficient of such a polynomial is calculated. This expression (depending only on the suspension metrics) being equal to zero, has an obvious geometrical sense and is a necessary condition for the suspension bending.