A Sphere is Rigid.
References
Gray, A. Modern Differential Geometry of Curves and Surfaces. Boca Raton, FL: CRC Press, p. 377, 1993. O'Neill, B. Elementary Differential Geometry, 2nd ed. New York: Academic Press, p. 262, 1997.
O'Neill, B. Elementary Differential Geometry, 2nd ed. New York: Academic Press, p. 262, 1997.
