Frode Alfson Bjørdal  Frode Alfson Bjørdal is professor emeritus in philosophy at the University of Oslo, Norway, and professor colaborador at "Programa de pós-graduação em filosofia" at the Federal University of Rio Grande do Norte in Natal, Brazil. Bjørdal did his undergraduate studies in philosophy, logic, mathematics and economics at the University of Bergen, Norway, and was a DAAD-Stipendiat at the Johan Wolfgang von Goethe Universität in Frankfurt am Main, Germany, in 1985/86. He studied philosophy at University of California, Santa Barbara, United States, from 1988 to 1992, and got his PhD from there in 1993. He first worked at the Universities of Trondheim and Tromsø, and became a professor of philosophy at the University of Oslo where he worked from 1996 to 2013. He is now a professor emeritus at the University of Oslo, , and as from 2013 he is also a professor colaborador at the Federal University of Rio Grande do Norte. Bjørdal has published on alternative set theories, semantics for modal logics and on modal ontological arguments in the Gödelian tradition. Eight of his publications are reviewed in Mathematical Reviews.