2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194378We study one-field open inflationary models in a universe dominated by tachyon matter. In these scenarios, we determine and characterize the existence of the Coleman-De Lucia (CDL) instanton. Also, we study the Lorentzian regime, that is, the period of inflation after tunnelling has occurred.13 pages, 7 figures. Accepted by Physics Letters BGeneral Relativity and Quantum Cosmologytext