#initial-plan

Question 1: Single choice

Plan-space planning starts from a partial plan with two dummy actions, $A_0$ and $A_\infty$ . What are they?

$A_0$ has the start state as its effects; $A_\infty$ has the goal as its preconditions1
$A_0$ has the goal as its effects; $A_\infty$ has the start state as its preconditions2
Both have no preconditions and no effects; they only mark the start and end3
$A_0$ holds every action applicable in the start state, $A_\infty$ every relevant action4