What is the difference in 'logical array blocked' and array list B, and what do they represent?
In the pseudocode, T array means an array where each element has type T.  Logical is the type of a boolean (i.e., it can hold the value true or false).  Integer list is the type of a list of integers.

Thus, in the pseudocode, logical array blocked(n) is the declaration of an array called blocked containing n elements, where each element is a boolean.  integer list array B(n) is the declaration of an array called B containing n elements, where each element is a list of integers.

$V_K$ isn't clearly defined, but from context, I'd guess it is the set of vertices in $A_K$.