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a_n <= a_{n+m} <= a_n + a_m

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October 11, 2010
inequalitieslimitalgebra unsolvedalgebra

Problem Statement

Let (an)1(a_n)_1^{\infty} be a sequence such that anan+man+ama_n \le a_{n+m} \le a_n + a_m for all positive integers nn and mm. Prove that ann\frac{a_n}{n} has a limit as nn approaches infinity.