Multi-pole soliton of discrete integrable equations and modified Riemann-Hilbert approach: discrete Hirota equation

Abstract In this study, the Riemann-Hilbert approach was developed and applied to the discrete Hirota equation. We constructed a modified Riemann-Hilbert problem compatible with the discrete Hirota equation and derived a reconstruction formula for its solutions. Because the characteristic function contains a potential, we modify the Riemann-Hilbert approach to make the Riemann-Hilbert matrix have good asymptotic properties. We believe that the modified Riemann-Hilbert approach can also be applied to other discrete integrable models. By using the direct method of Laurent series, we obtained the expression of multi-pole solutions for the discrete Hirota equation and demonstrated the dynamic behavior of some solutions.