2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63595We give various characterizations of into (not necessarily onto) complete isometries between $C^*$-algebras, generalizing a classical result of Holsztynski. Our results are related to a natural embedding of the noncommutative Shilov boundary in a second dual.Operator AlgebrasFunctional Analysistext