I roto i te 1887, haere Cesàro tata ki te kī i te whakamāramatanga o (C, n) tāpiritanga, engari i hoatu e ia he torutoru anake tauira. I roto i ngā, tāpiri ia 1 − 2 + 3 − 4 +..., ki te 1⁄4 e te tikanga e taea te rephrased rite (C, n) engari kihai i tika rite taua i te wa. Whakamāramatia e ia te tikanga (C, n) i roto i 1890 i roto i te tikanga ki te kī i tona taurangi e ko te Cauchy o te (C, n) -summable raupapa me te (C, m-summable raupapa) he tonu te hua (C, n + m-summable raupapa) + (C, n + m 1) rite te tahi atu raupapa. Pātai: He aha te hua (C, n)?
(C, n) Ko te