fact: Definition CauchyR x := BR_seq x /\ forall e, inc e BQps -> exists2 N, natp N & forall n m, natp n -> natp m -> N <=c n -> N <=c m -> BRabs ((Vg x n) -r (Vg x m)) <r (BR_of_Q e).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)