Asma Al Rwaily
In this paper, we introduce and investigate a new class of bounded linear operators on a Hilbert space, called the polynomially quasi-mth Helton class of operators of order mโโ. This class is defined through a vanishing operator relation involving a polynomial perturbation of the Helton operator map, namely. ๐ซ(๐)*ฮฆ(โฌ;๐)m(โ)๐ซ(๐)=0, for some nonconstant polynomial ๐ซ, where ฮฆ(โฌ;๐) denotes the Helton operator map given by ฮฆ(โฌ;๐)(X)=โฌX-X๐, so that ฮฆ(โฌ;๐)m(โ)=โj=0m(-1)j(mj)โฌj๐m-j. This framework extends the classical Helton class and the quasi-Helton class of order m by incorporating polynomial operator relations. We establish several fundamental properties of this class and investigate its structural behavior. In particular, we obtain characterizations, study stability properties, and discuss connections with well-known operator classes such as m-isometric and m-symmetric operators. Our results provide a unified framework that highlights the interplay between polynomial operator expressions and quasi-Helton-type relations in operator theory.