If X is a real n-dimensional space provided with a subnorm pi, then th
e inequality xi greater than or equal to pi(x) defines a so-called hyp
erbolic cone in E = R + X. In this case the Perron-Frobenius theory ad
mits some special features. A relevant characterization of nonnegative
operators in a matrix form is given first. Auxiliary information from
spectral theory and from the geometry of subnormed spaces is collecte
d as preparation.