About C-rigid quadrics

In the article strongly nondegenerate (k, n)-quadrics all of whose linear automorphisms are of the formzz, ¦¦2, {0} are considered. Quadrics all of whose linear automorphisms are of this form were calledc-rigid by V. Beloshapka. The main result of the article is the following: anyc-rigid strongly nondegenerate (k, n)-quadric has no nonlinear automorphisms. A table indicating the relationship between linear and nonlinear automorphisms for (k, n)-quadrics is presented.Translated fromMatematicheskie Zametki, Vol. 59, No. 2, pp. 224–229, February, 1996.