Poincaré–Bertrand and Hilbert formulas for the Cauchy–Cimmino singular integrals

The Cimmino system offers a natural and elegant generalization to four-dimensional case of the Cauchy–Riemann system of first order complex partial differential equations. Recently, it has been proved that many facts from the holomorphic function theory have their extensions onto the Cimmino system theory. In the present work a Poincaré–Bertrand formula related to the Cauchy–Cimmino singular integrals over piecewise Lyapunov surfaces in R⁴ is derived with recourse to arguments involving quaternionic analysis. Furthermore, this paper obtains some analogues of the Hilbert formulas on the unit 3-sphere and on the 3-dimensional space for the theory of Cimmino system.