Template-Type: ReDIF-Paper 1.0
Author-Name: Mihir  Bhattacharya
Author-Name-First: Mihir 
Author-Name-Last: Bhattacharya
Author-Email: mihir.bhattacharya@ashoka.edu.in
Author-Workplace-Name: Ashoka University
Title: Contraction consistent aggregation on trees
Abstract: We study contraction consistent social choice functions (s.c.f.) in a setting where voters have single-peaked preferences over a tree. This is relevant in settings where alternatives are locations spread out on a tree and a location needs to be selected for provision of a public good. An s.c.f. is contraction consistent if its outcome at any profile does not change when the profile is restricted to any subset consisting of the outcome. We show that q-threshold rules on trees} are the only s.c.f.s which satisfy contraction consistency, unanimity  and anonymity. These s.c.f.s specify, for each alternative, thresholds which are decreasing (increasing) on every path from a given node. These s.c.f.s then select from the range, the unique alternative which is the smallest (greatest) alternative in any restricted vote profile that receives more additive votes than the threshold assigned to it. These s.c.f.s are generalizations of min, max, and median s.c.f.s when restricted to paths.
length: 25
Creation-Date: 20230316
Revision-Date: 20230809
Publication-Status: 
File-URL:https://dp.ashoka.edu.in/ash/wpaper/paper96_0.pdf
File-Format: Application/pdf 
Number: 96
Keywords: Contraction consistency
Keywords: single-peaked preferences
Keywords: social choice functions
Keywords: trees
Handle: RePEc:ash:wpaper:96