  In this paper, we propose a polar coding based scheme for set reconciliation
between two network nodes. The system is modeled as a well-known Slepian-Wolf
setting induced by a fixed number of deletions. The set reconciliation process
is divided into two phases: 1) a deletion polar code is employed to help one
node to identify the possible deletion indices, which may be larger than the
number of genuine deletions; 2) a lossless compression polar code is then
designed to feedback those indices with minimum overhead. Our scheme can be
viewed as a generalization of polar codes to some emerging network-based
applications such as the package synchronization in blockchains. Some
connections with the existing schemes based on the invertible Bloom lookup
tables (IBLTs) and network coding are also observed and briefly discussed.
