2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50446These are notes on twisted K-homology theory and twisted Ext-theory from the C*-algebra viewpoint, part of a series of talks on ``C*-algebras, noncommutative geometry and K-theory'', primarily for physicists.12 pages, Latex2e (only funding acknowledgements revised)High Energy Physics - Theorytext