We give an alternative proof of Hua’s theorem that each large N≡5 (mod 24) can be written as a sum of five squares of primes. The proof depends on an estimate of exponential sums involving the Möbius function.
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Wenjia ZHAO. Hua’s theorem on five squares of primes. Front. Math. China, 2020, 15(4): 835-850.
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