Different search strategies- artificial intelligence:

To help us think about the different search strategies, we use two analogies. Firstly, we suppose that the professor keeps an agenda of actions to undertake, such as: add an 'A' to the string 'AN'. So, the agenda consists of pairs(S,O) of states and operators, whereby the operator is to be applied to the state. The action at the top of the agenda is the one which is carried out, then that action is removed. How actions are added to the agenda differs for each search strategy. Secondly, we think of a search graphically: by making each state a node in a graph and each operator an edge, we can think of the search progressing as movement from node to node along edges in the graph. We then allow ourselves to talk about nodes in a search space (rather than the graph) and we say that a node in a search space has been expanded if the state that node represents has been visited and searched from. Note that graphs which have no cycles in them are called trees, and many AI searches can be represented as trees.