On \(L^ 1\)-convergence of a modified cosine sum (Q1207758)

The concept of quasi-convex sequence was generalized by \textit{S. Sidon} [J. Lond. Math. Soc. 14, 158-160 (1939; Zbl 0021.40301)]. Later on this was further generalized by the reviewer [Indian J. Pure Appl. Math. 8, 784-790 (1977; Zbl 0415.42008)]. Using this concept the author proves a theorem which is a generalization of a previous result of \textit{S. Kumari} and \textit{B. Ram} [Indian J. Pure Appl. Math. 19, No. 11, 1101-1104 (1988; Zbl 0666.42003)] on \(L^ 1\)-convergence of a modified cosine sum.