I started doing mathematical research during my university studies in chemistry, physics, and mathematics. A decade later, this research work was supplemented by creating a pedagogical project based on the comparison of plane geometry and spherical geometry. I designed a set of construction materials for spherical geometry that was first manufactured by the Hungarian TANÉRT Company in 1986. The improved version was produced and distributed by the Californian company Key Curriculum Press in 1996. I have been teaching this project for future elementary, secondary and even kindergarten teachers at two departments of Eötvös Loránd University. 

I have published articles, book chapters and books in several languages, both in mathematical research (number systems, axioms of geometry, multidimensional geometries), and the pedagogy of mathematics (comparative geometry between different geometric systems). Together with my colleague László Rozgonyi, I co-authored a chapter of a book on geometric concepts in navigation for future pilots. I have given lectures and led courses on the above topics in many countries. Now retired, I still love teaching. I am proud that my university courses are attended by students with a wide variety of backgrounds, from kindergarten teachers to technical and scientific professionals.

István Lénárt
Eötvös Loránd University,
Faculty of Science, Mathematics Teaching and Education Centre
Faculty of Primary and Preschool Education, Department of Mathematics