  Barter exchange studies the setting where each agent owns a good, and they
can exchange with each other if that gives them more preferred goods. This
exchange will give better outcomes if there are more participants. The
challenge here is how to get more participants and our goal is to incentivize
the existing participants to invite new participants. However, new participants
might be competitors for the existing participants. Therefore, we design an
exchange mechanism based on the classical Top Trading Cycle (TTC) algorithm to
solve their conflicts. Our mechanism is truthful in terms of revealing their
preferences and also guarantees that inviting all their neighbors is a dominant
strategy for all participants. The mechanism can be applied in settings where
more participants are preferred but no extra budget to reach new participants.
