The document discusses AND/OR graphs, which are a type of graph or tree used to represent solutions to problems that can be decomposed into smaller subproblems. AND/OR graphs have nodes that represent goals or states, with successors labeled as either AND or OR branches. AND branches signify subgoals that must all be achieved to satisfy the parent goal, while OR branches indicate alternative subgoals that could achieve the parent goal. The graph helps model how decomposed subproblems relate and their solutions combine to solve the overall problem.

1. AND/OR graph
ALI A. JALIL

2. AND/OR graph
 A form of graph or tree used in problem solving and problem
decomposition.
 The nodes of the graph represent states or goals and their successors are
labeled as either AND or OR branches.
 The AND successors are sub goals that must all be achieved to satisfy
the parent goal,
 while OR branches indicate alternative sub goals, any one of which could
satisfy the parent goal.

3. AND/OR graph

4. AND/OR graph
 AND-OR graph (or tree) is useful for representing the solution of
problems that can be solved by decomposing them into a set of smaller
problems, all of which must then be solved.
 One AND arc may point to any number of successor nodes, all of which
must be solved in order for the arc to point to a solution.

5. AND/OR graph - Example
 In figure the top node A has been expanded
producing two area one leading to B and
leading to C-D .
 the numbers at each node represent the value
of f ' at that node (cost of getting to the goal
state from current state).
 For simplicity, it is assumed that every operation
(i.e. applying a rule) has unit cost, i.e., each are
with single successor will have a cost of 1 and
each of its components.
 With the available information till now , it
appears that C is the most promising node to
expand since its f ' = 3 , the lowest but going
through B would be better since to use C we
must also use D' and the cost would be
9(3+4+1+1). Through B it would be 6(5+1).
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