Çakan, CelalÇoşkun, HüsamettinAltay, Bilal2024-08-042024-08-0420091303-50102651-477Xhttps://search.trdizin.gov.tr/tr/yayin/detay/92449https://hdl.handle.net/11616/89047The famous Knopp Core of a single sequence was extended to the P- core of a double sequence by R.F. Patterson. Recently, the MR-core and σ-core of real bounded double sequences have been introduced and some inequalities analogues to those for Knoop’s Core Theorem have been studied. The aim of this paper is to characterize a class of four-dimensional matrices, and so to obtain necessary and sufficient conditions for a new inequality related to the P- and σ-cores.eninfo:eu-repo/semantics/openAccessArticle381515892449