Oka-analyticity of the essential spectrum
Using the fundamental notions of the quaternionic analysis we show that there are no 4-dimensional almost Kähler manifolds which are locally conformally flat with a metric of a special form.
Several sets of quaternionic functions are described and studied with respect to hyperholomorphy, addition and (non-commutative) multiplication, on open sets of ℍ, then Hamilton 4-manifolds analogous to Riemann surfaces, for ℍ instead of ℂ, are defined, and so begin to describe a class of four-dimensional manifolds.
We consider a certain analog of Cauchy type integral taking values in a three-dimensional harmonic algebra with two-dimensional radical. We establish sufficient conditions for an existence of limiting values of this integral on the curve of integration.
The purpose of this paper is to study the Sarason’s problem on Fock spaces of polyanalytic functions. Namely, given two polyanalytic symbols and , we establish a necessary and sufficient condition for the boundedness of some Toeplitz products subjected to certain restriction on and . We also characterize this property in terms of the Berezin transform.