Savaş, EkremŞevli, Hamdullah2020-11-212020-11-2120100139-9918https://doi.org/10.2478/s12175-010-0028-4https://hdl.handle.net/11467/3548A lower triangular infinite matrix is called a triangle if there are no zeros on the principal diagonal. The main result of this paper gives a minimal set of sufficient conditions for a double triangle T to be a bounded operator on Ak2; i. e., T ? B (Ak2) for the sequence space Ak2 defined below. As special summability methods T we consider weighted mean and double Cesàro, (C, 1, 1), methods. As a corollary we obtain necessary and sufficient conditions for a double triangle T to be a bounded operator on the space BV of double sequences of bounded variation. © 2010 Versita Warsaw and Springer-Verlag Wien.eninfo:eu-repo/semantics/openAccessAk spacesBounded operatorDouble sequence spaceTriangular matricesWeighted mean methodsArticle604495506Q4WOS:000279698300007Q22-s2.0-7795445451910.2478/s12175-010-0028-4