As a special issue of this highly esteemed journal, we were pleased to invite the interested authors to contribute their original research papers as well as good expository papers to this special issue that will make better improvement on the theory of Clifford analysis and its application to mathematical physics, providing new approaches to differential geometry using Clifford’s geometric analysis. We suggested the following topics: theory of hyperholomorphic functions, regular functions, monogenic functions, hypercomplex number, dual number systems, spilt number systems, bicomplex numbers, and split biquaternions and pseudoquaternions; analytic extensions and applications; general theory of complex analytic spaces; complex partial differential operators, quaternion matrix equations, and generalized Cauchy-Riemann systems; domains of hyperholomorphy; and complex function spaces and hyperconjugate harmonic function. Certain papers that have significant results on complex analysis in the widest sense were intended to be welcome.

Besides some papers belonging to the above-intended topics, we are also happy to publish, in this special issue, several other papers regarding analytic number theory, -series and combinatorics, and special functions and the theory of group representations.

Kwang Ho Shon
Junesang Choi
Tatsuhiro Honda