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*