# Search Terminology

**Problem Space**: It is the environment in which the search takes place. (A set of states and set of operators to change those states)**Problem Instance**: It is Initial state + Goal state**Problem Space Graph**: It represents problem state. States are shown by nodes and operators are shown by edges.**Depth of a problem**: Length of a shortest path or shortest sequence of operators from Initial State to goal state.**Space Complexity**: The maximum number of nodes that are stored in memory.**Time Complexity**: The maximum number of nodes that are created.**Admissibility**: A property of an algorithm to always find an optimal solution.**Branching Factor**: The average number of child nodes in the problem space graph.**Depth**: Length of the shortest path from initial state to goal state.