Multiplicative functions supported on the $k$-free integers with small partial sums

We provide examples of multiplicative functions $f$ supported on the $k$-free integers such that at primes $f(p)=\pm 1$ and such that the partial sums of $f$ up to $x$ are $o(x^{1\mathrm{/}k})$. Further, if we assume the Generalized Riemann Hypothesis, then we can improve the exponent $1\mathrm{/}k$: There are examples such that the partial sums up to $x$ are $o(x^{1\mathrm{/}(k+\frac{1}{2})+ϵ})$, for all $ϵ>0$. This generalizes to the $k$-free integers the results of Aymone, `` A note on multiplicative functions resembling the {M}"{o}bius function’', J. Number Theory, 212 (2020), pp. 113–121.