### A conference celebrating Luis Martínez Alonso's scientific career

The academic career of Luis Martínez Alonso spans almost five decades, starting with his appointment as "Profesor Ayudante" (Teaching Assitant) at Universidad Complutense de Madrid's Department of Theoretical Physics in 1972. Luis was succesively appointed Associate Professor in 1979 and Full Professor in 1986, becoming Emeritus Professor in 2019 (all at UCM). Over the years 1979–90 Luis regularly visited the Mathematical Physics Laboratory of the Université de Montpellier as Maître de Conférences. He was also appointed BBVA Visiting Professor at Cambridge University (July-December 2001), and throughout the years has visited on a regular basis the universities of La Sapienza, Roma Tre and Lecce. Luis's career has touched upon multiple areas of mathematical and theoretical physics, with important contributions to the theory of classical and quantum integrable systems which have earned him widespread international recognition. Among his most significant results we could mention the determination of the general invariants under the adjoint action of a finite-dimensional complex Lie algebra (in particular, Casimir operators), his now famous counterexample to the Gel'fand–Kirillov conjecture, the generalization of KdV-type hierarchies using energy-dependent Schrödinger operators, the characterization of the interaction of solitons with radiation, the study of the dispersionless limit of integrable systems, etc. In particular, his long-term collaboration with Alexei Shabat has given rise to a remarkable integrable PDE in four dimensions, commonly known in the literature as the Martinez Alonso–Shabat equation, which has been intensively studied. More recently, Luis has also applied the techniques of the theory of integrable systems to solving problems in such diverse fields as random matrix theory or inflationary cosmology, to name only a few. Throughout the years Luis has been a source of constant inspiration for all of us working in mathematical and theoretical physics at the Department, and is one of the professors most highly rated by the students of the Physics Faculty, where he has taught numerous undergraduate, master and Ph. D. courses. He is also well known as a die-hard Real Madrid fan … but that's a different story!