Solution
= Solution
The magnetic gauge group is $Sp(\widetilde N_c)$ with $\widetilde N_c=N_f-N_c-2$. Repeating the gauge-anomaly cancellation gives
$$
R[q]=1-\frac{\widetilde N_c+1}{N_f}
=\boxed{\frac{N_c+1}{N_f}}.
$$
= Solution
The magnetic gauge group is $Sp(\widetilde N_c)$ with $\widetilde N_c=N_f-N_c-2$. Repeating the gauge-anomaly cancellation gives
$$
R[q]=1-\frac{\widetilde N_c+1}{N_f}
=\boxed{\frac{N_c+1}{N_f}}.
$$