Such that for each vertex vis v δv is δ v i and γ

such that for each vertex ˜ v
i,s
∈ V , δ (˜ v
i,s
) = δ ( v
i
) and Γ(˜ v
i,s
)
20

21

23

24

cycles of length 4 are potentially bad, see
P. O. Vontobel and R. Koetter, “Graph-cover decoding and
finite-length analysis of message-passing iterative decoding of
LDPC codes,” preprint, available online at
abs/cs/0512078
•