 We now turn to a more complicated action: the semi-private announcement of p to agent a (sometimes called the “semi-public announcement” of p to agent a). The idea of this action is that agent a is told that p is true, the other agents know that a is told the truth value of p, but these other agents do not know what it is exactly that a is told. This suggests an action model with two events, one for each thing that a might be told: an event e that announces p and event f that announces \(\lnot p\). Agent a is to know which event occurs, whereas all other agents are to be uncertain as to which event occurs. This leads us to the action model \(\frac12\Pri_a(p)\) pictured in Figure 5. 