Professor Pedro M. Gadea taught at the Universities of Santiago de Compostela and Valladolid, Spain. He is now a scientific researcher at the Instituto de Física Fundamental, CSIC, Madrid, Spain. He has published more than sixty research papers on several topics of differential geometry, algebraic topology and automatic speech recognition. He has also been advisor of four PhD theses. His current interests are in differential geometry, and specifically in Riemannian, Kähler, quaternion-Kähler and Spin(9) manifolds and structures, and their applications to supergravity. Outside of mathematics, his chief interests are history and minerals. Professor J Muñoz Masqué taught at the University of Salamanca, Spain. He is currently a scientific researcher at the Instituto de Seguridad de la Información (ISI), CSIC, Madrid, Spain. He has written more than one hundred research articles on calculus of variations, Riemannian geometry, differential invariants, gauge theories, and public key cryptography, and he is currently studying on these topics. Outside of mathematics, his chief interests is Spanish poetry. Professor Ihor Mykytyuk teaches at the Pedagogical University of Cracow, Poland. He is Head of Department at the Pidstryhach Institute of Applied Problems of Mechanics and Mathematics, NASU, L'viv, Ukraine. He has published more than thirty research papers on several topics of differential geometry, Lie groups theory and integrable dynamical systems. He is a co-author of two monographs on these topics. His current interests are in differential geometry and Lie groups theory, and specifically in Riemannian, Kähler, hyper-Kähler and Spin(9) structures possessing rich groups of symmetries. Outside of mathematics, his main interests are history and bicycle travels.