• Congruences and Exponential Sums with the Euler Function 

    Banks, William David, 1964-; Shparlinski, Igor E. (2004)
    We give upper bounds for the number of solutions to congruences with the Euler function φ(n) and with the Carmichael function λ(n). We also give nontrivial bounds for certain exponential sums involving φ(n). Analogous ...