Social welfare and social choice in different individuals’ preferences

This paper discusses both social welfare and social choice using Arrow’s impossibility theorem for multi-profile preference case and two versions of it for single-profile preference case. Between these two versions first one assumes a two-individual society and the second one, which is similar to a theorem of Pollak, assuming two or more individuals. In single-profile version decisiveness, simple and complex diversity must occur. This paper considers a special case of Arrow’s theorem, namely single-profile preference. Diversity and decisiveness of preferences are discussed for two individuals and more than two individuals in a society.