Answer
CHECK STEP BY STEP WORK
Work Step by Step
We just repeat the discussion in the text, with the roles of the rows and columns interchanged: To assert that column j contains the number n.
We form v;=1 p(i,j,n). To assert that column j contains all 9 numbers.
We form the conjunction of these disjunctions over all nine possible values of n, giving us /\~=l Vi=l p( i, j, n).
To assert that every column contains every number, we take the conjunction of /\~=l Vi=1 p(i,j,n) over all
nine columns.
This gives us /\~= 1 /\~= 1 v;=1 p( i, j, n).
