Sozen, Esra Ozturk2026-04-252026-04-2520250354-5180https://doi.org/10.2298/FIL2522707Ohttps://hdl.handle.net/11486/8546In this essay (amply) cofinitely delta(ss)-supplemented modules are presented and fundamental algebraic features of these modules are examined. Privately, a ring characterization theorem is presented as follows. R is a delta(ss)-perfect ring if and only if every (projective) left R-module is (amply) cofinitely delta(ss)-supplemented. Moreover, the question when cofinitely delta(ss)-supplemented modules are cofinitely sssupplemented is checked. With this aim we define left triangle(ss)-rings and the fact that a ring R is a left triangle(ss)-ring if and only if each cofinitely delta(ss)-supplemented R-module is cofinitely ss-supplemented is proven.eninfo:eu-repo/semantics/openAccessleft delta(ss)-perfect ring(amply) cofinitely delta(ss)-supplemented moduleleft triangle(ss)-ringArticle39227707771910.2298/FIL2522707O2-s2.0-105020467925Q2WOS:001629557300001Q20000-0002-2632-2193