Birkenmeier, Gary F.Tercan, Adnan2024-06-122024-06-122021-08-010219-4988https://doi.org/10.1142/S0219498821501371https://hdl.handle.net/11452/42041In this paper, we introduce and investigate three new versions of the Rickart condition for rings. These conditions, as well as, three new corresponding regularities are defined using projection invariance. We show how these conditions relate to each other as well as their connections to the well-known Baer, Rickart, quasi-Baer, p.q.-Baer, regular, and biregular conditions. Applications to polynomial extensions and to triangular and full matrix rings are provided. Examples illustrate and delimit results.eninfo:eu-repo/semantics/closedAccessIdempotentsExtensionsSetsRight rickart ringRight p.p ringBaer ringP-baer ringProjection invariantGeneralized triangular matrix ringMatrix ringPolynomial extensionsRegular ringExchange ringBanach algebraScience & technologyPhysical sciencesMathematics, appliedMathematicsMathematicsArticle000681763500019200810.1142/S0219498821501371