Describe the mistake
I think I found an error in the SVM section: you write in the remark after Eq. (12.42) that the optimal value for the off-set for the Soft-Margin SVM is given by the median of the numbers
$$ | y_n - \langle w^*, x_n\rangle| $$
for all $n$ such that $\alpha_n\neq 0$. Instead, I think it should be the median of $(y_n - \langle w^*, x_n\rangle)$ (without absolute values).
Describe the mistake I think I found an error in the SVM section: you write in the remark after Eq. (12.42) that the optimal value for the off-set for the Soft-Margin SVM is given by the median of the numbers
$$ | y_n - \langle w^*, x_n\rangle| $$
for all $n$ such that $\alpha_n\neq 0$. Instead, I think it should be the median of $(y_n - \langle w^*, x_n\rangle)$ (without absolute values).
Location
Proposed solution As explained above, I think one has to remove the absolute values.
Additional context I typed a proof in Prop. 3.30 in https://pbrdng.github.io/MathData-SoSe22/MathData.pdf. Feel free to copy it.