“…In addition, this model has proved to be useful to describe the learning of other mathematical topics such as local approximation (Llorens & Pérez-Carreras, 1997), convergence of sequences (Navarro & Pérez-Carreras, 2006), convergence of series (Jaramilllo, 2000) or functions (Nisawa, 2018). Thus, González et al (2021) perform a theoretical analysis that produces a characterization of the learning of graph theory through four levels of reasoning under the lens of the Van Hiele model, whose validity must be tested in empirical studies as the present paper. This characterization is organised through the development of the processes of reasoning that students may activate when dealing with graphs: recognition, use and formulation of definitions, classification, and proof, thus providing descriptors of levels for each process.…”