# Search Terminology

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FreelancingGig— [October 10, 2017](/content/blog/glossary/search-terminology/index.html)

- **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.