RIEMANN HYPOTHESIS, MÖBIUS’ FUNCTION AND RANDOM MULTIPLICATIVE FUNCTIONS (Joint work with Y.-K. Lau & G. Tenenbaum) Abstract. Let P denote the set of primes and {f (p)}p∈P be a sequence of independent Bernoulli random variables taking values ±1 with probability 1/2. Extending f by multiplicativity to a random multiplicative function f supported on the squarefree integers, we prove that, for any ε > 0, the estimate X √ f (n) x (log log x)3/2+ε n6x holds almost surely—thus qualitatively matching the law of iterated logarithm, valid for independent variables. This inequality improves significantly corresponding result of Wintner, Erdős and Halász. 1