2 papers
math.GR2015
Fixed subgroups are compressed in surface groups
Qiang Zhang, Enric Ventura, Jianchun Wu
For a compact surface (orientable or not, and with boundary or not) we show that the fixed subgroup, , of any family of endomorphisms of is c…
cs.GT2014
Efficiency of Truthful and Symmetric Mechanisms in One-sided Matching
Marek Adamczyk, Piotr Sankowski, Qiang Zhang
We study the efficiency (in terms of social welfare) of truthful and symmetric mechanisms in one-sided matching problems with {\em dichotomous preferences} and {\em normalized von…