Robin inequality for n/phi(n)

Let (n) be the Euler function, (n) =₃ ₍d the sum of divisors function and =0. 577 the Euler constant. In 1982, Robin proved that, under the Riemann hypothesis, (n) /n 5040 and that this inequality is equivalent to the Riemann hypothesis. The aim of this paper is to give a similar equivalence for n/ (n).