Local and global bounds for ratios of norms, and minimal and maximal n
orms, are constructed for pairs and ensembles of quadratic norms on R-
k, with corresponding results for Mahalanobis distance functions. Thes
e support envelopes for distributions of certain quadratic forms in Ga
ussian variates. Applications are noted in the use of quadratic classi
fication rules and in assessing hit probabilities in ballistic systems
. (C) 1997 Elsevier Science Inc.