fact: Definition dproj d s t := locked (\row_(j < n) if j \in s then t ``_ j else d ``_ j).
imports: mathcomp(all_ssreflect ssralg fingroup finalg zmodp matrix) Reals mathcomp(Rstruct) ssr_ext ssralg_ext ssrR Reals_ext f2 summary subgraph_partition tanner tanner_partition fdist channel checksum