Some results on monotonicity

In this thesis, we investigate several issues concerning social choice rules which satisfy different degrees of Maskin type monotonicities. Firstly, we introduce g −monotonicity and monotonicity region notions which enable one to compare monotonicity properties of non Maskin monotonic social choice rules. We compare self-monotonicities of standard scoring rules and study monotonicity of Majoritarian compromise. Secondly we determine domains of impossibility and possibility when the individual preferences are clustered around two opposing norms and the degree of clustering is measured via the M anhattan metric. In the last chapter we investigate the relation between monotonicity and dictatoriality when agents are allowed to have thick indifference classes.