Clemens Puppe is Professor of Economic Theory at the Karlsruhe Institute of Technology (KIT), where he also serves as co-director of the Institute of Economics. He studied Mathematics and Philosophy at Heidelberg University and the Free University of Berlin, and earned his Ph.D. from the University of Karlsruhe with a thesis on individual decision-making under uncertainty. His research focuses on microeconomic theory, particularly decision theory and social choice theory, with contributions to the measurement of freedom, diversity theory, judgment aggregation, and strategy-proof voting rules.Prof. Puppe has held academic positions at the University of Vienna, the University of Bonn, and visiting appointments at institutions including Harvard University, the University of Auckland, and Oxford University. He is co-editor of the Handbook of Rational and Social Choice and served as managing editor of Social Choice and Welfare from 2012 to 2024. Arkadii M. Slinko is currently Professor of Mathematics at the University of Auckland, New Zealand. Before taking this position in 1993 he was a Senior Research Fellow of the interdisciplinary Institute of Systems Analysis of Russian Academy of Sciences in Moscow. He has published extensively in a wide range of journals in mathematics, computer science, economics, and politics. His current research focuses on the mathematics of social choice, game theory, and secret sharing.