2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76614We investigate the system TRC of combinatory logic that is equiconsistent with New Foundations. We prove that various unstratified combinators do not exist in TRC.10 pages. Available also from http://www.math.psu.edu/jech/preprints/Logictext