 
Summary: Distributed Computing manuscript No.
(will be inserted by the editor)
Dana Angluin · James Aspnes · David Eisenstat
A Simple Population Protocol for Fast Robust
Approximate Majority
Received: date / Accepted: date
Abstract We describe and analyze a 3state oneway
population protocol to compute approximate majority
in the model in which pairs of agents are drawn uni
formly at random to interact. Given an initial configu
ration of x's, y's and blanks that contains at least one
nonblank, the goal is for the agents to reach consen
sus on one of the values x or y. Additionally, the value
chosen should be the majority nonblank initial value,
provided it exceeds the minority by a sufficient margin.
We prove that with high probability n agents reach con
sensus in O(n log n) interactions and the value chosen is
the majority provided that its initial margin is at least
(
