In paper 'LOW-LATENCY LIST DECODING OF POLAR CODES WITH DOUBLE THRESHOLDING', the authors mention that a small and regular architecture of the memory and processing element (PE) can be used for the list decoding, and they adopt the same path path metrics of the two extensions of the path p^i_l, and use the same approximation as that paper. You've also read that paper. Provide the full name of that paper.