proposition: Lemma ereal_series k : \sum_(k <= i <oo) f i = \sum_(i <oo | (k <= i)%N) f i.
proof: Proof. rewrite ereal_series_cond; congr (limn _); apply/funext => n. by apply: eq_big => // i; rewrite andbT. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(set_interval) reals ereal signed topology normedtype landau