agents via two existing mechanisms: LIKE and BALANCED LIKE. The LIKE mechanism is
strategy-proof whereas the BALANCED LIKE mechanism is not. Whilst LIKE is strategy-
proof, we show that it is not group strategy-proof. Indeed, our first main result is that no
online mechanism is group strategyproof. We then focus on pure Nash equilibria of these
two mechanisms. Our second main result is that computing a pure Nash equilibrium is …