Already for a long time it is known that quaternionic polynomials whose coefficients are located only at one side of the powers, may have two classes of zeros: isolated zeros and spherical zeros. Only recently a classification of the two types of zeros and a means to compute all zeros of such polynomials have been developed. In this investigation we consider quaternionic polynomials whose coeff...

Atomic Functions are widely used in different applications in image processing, pattern recognition, computational physics and also in the digital interpretation of signal measurements. The main contribution of this work is to develop a Quaternionic Atomic Function Wavelet as a new quaternionic image wavelet transform. This filter have a real part and three imaginary parts (i, j, k) of the Quat...

The analytic signal of a real signal is a standard concept in 1D signal processing. However, the deenition of an analytic signal for real 2D signals is not possible by a straightforward extension of the 1D deenition. There rather occur several diierent approaches in the literature. We review the main approaches and propose a new deenition which is based on the recently introduced quaternionic F...

The conformal infinity of a quaternionic-Kähler metric on a 4n-manifold with boundary is a codimension 3-distribution on the boundary called quaternionic contact. In dimensions 4n− 1 greater than 7, a quaternionic contact structure is always the conformal infinity of a quaternionic-Kähler metric. On the contrary, in dimension 7, we prove a criterion for quaternionic contact structures to be the...

The conformal infinity of a quaternionic-Kähler metric on a 4n-manifold with boundary is a codimension 3-distribution on the boundary called quaternionic contact. In dimensions 4n − 1 greater than 7, a quaternionic contact structure is always the conformal infinity of a quaternionic-Kähler metric. On the contrary, in dimension 7, we prove a criterion for quaternionic contact structures to be th...

We give an [Formula: see text] algorithm for computing the text]-dimensional persistent homology of a filtration clique complexes cyclic graphs on vertices. This is nearly quadratic in number vertices text], and therefore large improvement upon traditional algorithm, which cubic simplices dimension at most hence running time text]. Our applies, example, to Vietoris–Rips points sampled from curv...

In this paper, we introduce a new processing procedure for quaternionic signals through consideration of the well-known orthogonal matching pursuit (OMP), which provides sparse approximation. Due to quaternions noncommutativity, two quaternionic extensions are presented: the right-multiplication quaternionic OMP, that can be used to process right-multiplication linear combinations of quaternion...