Matrices of positive polynomials.
We investigate some aspects of maximum modulus sets in the boundary of a strictly pseudoconvex domain of dimension . If is a smooth manifold of dimension and a maximum modulus set, then it admits a unique foliation by compact interpolation manifolds. There is a semiglobal converse in the real analytic case. Two functions in with the same smooth -dimensional maximum modulus set are analytically related and are polynomially related if a certain homology class in vanishes or if is polynomially...
It is proved that the Fréchet algebra has exactly three closed subalgebras which contain nonconstant functions and which are invariant, in the sense that whenever and is a biholomorphic map of the open unit ball of onto . One of these consists of the holomorphic functions in , the second consists of those whose complex conjugates are holomorphic, and the third is .