Would someone be so kind to explain this to me:
πnk={1if k=argminj‖
Especially the \arg\min part.
(It’s from the k-means algorithm.)
Answer
\arg\min is argument of the minimum.
The simplest example is
\arg\min _{x} f(x) is the value of x for which f(x) attains its minimum.
for your example
x_n is known and depends on \pi_{nk}
and k equals to j such that \begin{Vmatrix}
x_n-\mu_j
\end{Vmatrix}^2 attains minimum among all values of \mu_j and given x_n.
hopefully that helps.
Attribution
Source : Link , Question Author : Olivier_s_j , Answer Author : phhu