this is equation of circuit a why 0 at circuit a exist and t

this is equation of circuit (a)

why \"0\" at circuit (a) exist?

and this is equation of circuit (b)

what I want to know is meaning of sentence given below.

Solution

why \"0\" at circuit (a) exist?

The LUT is optional (it can be NULL). If the LUT is not null, it can be used for display or for display and image processing. At circular (a), only two inputs are present and hence null for 1 input. 0 means null.

Circuit (b) has only two 3-LUTs.3-LUTs are required as there is four inputs w₁ to w₄.