Step Increase K Decrease K

$∣ \{ x_i : {{x_i}^{t-1}∈c_k , {x_i}^{t}∉c_k } \} ∣$

$∑↙{k=1}↖K ∑↙{x_i∈c_k} {‖ x_i - μ_k ‖^2}$