does any body know anything about horizontal and vertical propagation

Question

according to this diagram...how many people can get privileges? and what is a horizontal and vertical propagation?

did find something here which says

Suppose that Al grants SELECT to A2 on the EMPLOYEE relation with horizontal propaga-tion equal to 1 and vertical propagation equal to 2. A2 can then grant SELECT to at most one account because the horizontal propagation limitation is set to 1. Additionally, A2 cannot grant the privilege to another account except with vertical propagation set to 0 (no GRANT OPTION) or 1; this is because A2 must reduce the vertical propagation by at least 1 when passing the privilege to others. In addition, the horizontal propagation must be less than or equal to the originally granted hor-izontal propagation. For example, if account A grants a privilege to account B with the horizontal propagation set to an integer number j > 0, this means that B can grant the privilege to other accounts only with a horizontal propagation less than or equal to j. As this example shows, horizontal and vertical propagation techniques are designed to limit the depth and breadth of propagation of privileges.

how do i apply this to that question?

Answer 1

Horizontal propagation allows an account to grant privileges to at most i other accounts where i is specified. For example, {GRANT SELECT ON EMPLOYEE TO B WITH GRANT OPTION HORIZONTAL 3;} will allow B->C, B->D and B->E. Similarly, in the case of vertical propagation, {GRANT SELECT ON EMPLOYEE TO B WITH GRANT OPTION VERTICAL 3;} will allow B->C->D->E but not B->C->D->E->F.