Sever Y.Talo Ö.2024-07-222024-07-22201402365294http://akademikarsiv.cbu.edu.tr:4000/handle/123456789/16696Boos, Leiger and Zeller [1,2] defined the concept of e-convergence. In this paper we introduce the concepts of e-limit superior and inferior for real double sequences and prove some fundamental properties of e-limit superior and inferior. In addition to these results we define e-core for double sequences. Also, we show that that if A is a nonnegative Ceregular matrix then the e-core of Ax is contained in e-core of x, provided that Ax exists. © 2014, Akadémiai Kiadó, Budapest, Hungary.EnglishAll Open Access; Green Open AccessArticle10.1007/s10474-014-0447-8