2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/166185We prove that approximating the size of stopping and trapping sets in Tanner graphs of linear block codes, and more restrictively, the class of low-density parity-check (LDPC) codes, is NP-hard. The ramifications of our findings are that methods used for estimating the height of the error-floor of moderate- and long-length LDPC codes based on stopping and trapping set enumeration cannot provide accurate worst-case performance predictions.16 pages, 6 figure, submitted journal versionInformation Theorytext