Answer to Question #104129 in Functional Analysis for maria

Question

A metric space M is called a сomplete metric space if

Answer 1

A metric space M is called complete (or a Cauchy space) if every Cauchy sequence of points in M has a limit that is also in M or, alternatively, if every Cauchy sequence in M converges in M.

https://en.wikipedia.org/wiki/Complete_metric_space