  We examine regular and irregular repeat-accumulate (RA) codes with repetition
degrees which are all even. For these codes and with a particular choice of an
interleaver, we give an upper bound on the decoding error probability of a
linear-programming based decoder which is an inverse polynomial in the block
length. Our bound is valid for any memoryless, binary-input, output-symmetric
(MBIOS) channel. This result generalizes the bound derived by Feldman et al.,
which was for regular RA(2) codes.
