1. First, consider the block where the element x 1 As can be seen from the relationship matrix, x 1 is related to x2 and x6, so {x 1, x2, x6} is a block, and x3, x4 and x5 do not appear in this block.

2. Next, consider the block where element x3 is located. As can be seen from the relationship matrix, x3 is related to x4, x5 and x6, so {x3, x4, x5 and x6} is a block, and these two blocks already contain all the elements of X..

3. So the set formed by these two blocks is a cover of X, and the cover is {{x 1, x2, x6}, {x3, x4, x5, x6}}