EDITORIAL: “Solitons, Integrability, Nonlinear Waves: Theory and Applications” V. S. Gerdjikov, B. Prinari, V. V. Pukhnachev and M. D. Todorov Eur. Phys. J. Plus, 136 1 (2021) 41 Published online: 04 January 2021 DOI: 10.1140/epjp/s13360-020-01008-0