Problem, Problem space, Problem characteristics in AI

Helenjoy
5 min readJul 27, 2023

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Let’s explain the concepts of problem, problem space, and search in the context of artificial intelligence:

  1. Problem: A problem is a specific task or challenge that requires finding a solution or making a decision. In artificial intelligence, problems can vary in complexity and scope, ranging from simple tasks like arithmetic calculations to complex challenges such as image recognition, natural language processing, game playing, and optimization. Each problem has a defined set of initial states, possible actions or moves, and a goal state that needs to be reached or achieved.

For example, in a game of chess, the problem is to find a sequence of moves that lead to checkmate, while in route planning, the problem is to find the shortest path between two locations on a map.

  1. Problem Space: The problem space is the set of all possible states, actions, and transitions that can be encountered while attempting to solve a specific problem. It represents the entire landscape of potential solutions and paths from the initial state to the goal state.

In other words, the problem space defines all the possible configurations or arrangements of elements involved in the problem and the set of valid moves or actions that can be taken at each state. Each state in the problem space represents a specific configuration, and each action represents a possible move or step from one state to another.

For example, in the problem of route planning, the problem space includes all possible locations on the map as states and all valid roads or paths between them as actions.

  1. Search: Search is the process of exploring the problem space to find a sequence of actions or moves that lead to the goal state or a satisfactory solution. In AI, search algorithms are used to systematically navigate through the problem space and discover paths or solutions that satisfy the problem’s constraints and objectives.

The search process involves starting from the initial state and exploring possible actions to generate new states. These states are then evaluated based on certain criteria (e.g., distance to the goal, cost, or utility) to determine the most promising states to explore further. The process continues iteratively until the goal state is reached or a satisfactory solution is found.

There are various search algorithms used in AI, such as depth-first search, breadth-first search, A* search, and heuristic search. Each algorithm has its strengths and weaknesses, and the choice of search algorithm depends on the problem’s characteristics, size of the problem space, and the resources available.

In summary, a problem is a task or challenge that requires a solution, the problem space represents all possible configurations and actions related to the problem, and search involves exploring the problem space to find a sequence of actions leading to the desired goal or solution. Efficient search algorithms are essential in AI problem-solving to effectively navigate large and complex problem spaces and find optimal or near-optimal solutions.

To solve the problem of building a system you should take the following steps:

1. Define the problem accurately including detailed specifications and what constitutes a suitable solution.

2. Scrutinize the problem carefully, for some features may have a central effect on the chosen method of solution.

3. Segregate and represent the background knowledge needed in the solution of the problem.

4. Choose the best solving techniques for the problem to solve a solution

Problem characteristics are essential factors to consider when choosing the most suitable problem-solving method for a particular task. Let’s explore these characteristics in detail:

Is the problem decomposable?

The question of whether a problem is decomposable refers to whether it can be broken down into smaller, independent subproblems. Decomposable problems can be solved by tackling each subproblem individually, and their solutions can then be combined to solve the overall problem. Some problems, like complex integrals, can be decomposed into simpler subproblems, making it easier to find a solution using the divide-and-conquer approach. However, not all problems are decomposable, and some may require addressing as a whole without breaking them down into independent parts.

Can solution steps be ignored or undone?

The reversibility of solution steps refers to whether they can be ignored or undone if they prove to be unwise or lead to a dead end. In some problems, certain solution steps can be ignored without affecting the final result. In recoverable problems, solution steps can be undone to explore alternative paths. For instance, in the 8-puzzle, moves can be undone to try different arrangements of tiles. On the other hand, some problems have irreversible solution steps, like in chess, where once a move is made, it cannot be undone.

Is the problem’s universe predictable?

The predictability of a problem’s universe refers to whether the outcomes or states of the problem can be determined with certainty or if they involve uncertainty. Some problems have deterministic outcomes, meaning that the result is known and can be predicted with complete certainty based on the given conditions and rules. Other problems may involve uncertainty or randomness, leading to non-deterministic outcomes. For example, some optimization problems may have multiple potential solutions with different probabilities of being optimal.

Is a good solution absolute or relative?

The nature of a good solution can be either absolute or relative. An absolute solution is one where finding a single correct path or outcome is sufficient to achieve the desired goal. In problems like the water jug puzzle, finding any valid path to the solution is considered good enough. On the other hand, a relative solution is one that requires evaluating multiple possible paths or outcomes to find the best or optimal solution. Problems like the traveling salesman problem seek the shortest route among all possible routes, making it a relative solution.

Is the solution a state or a path?

The solution to a problem can be either a state or a path, depending on the nature of the problem. In some problems, the desired outcome is a specific state or configuration that satisfies the problem’s requirements. For instance, in the 8-puzzle, the solution is a specific arrangement of tiles in the goal state. In other problems, the solution involves finding a path or sequence of steps to reach the desired goal state. For example, in maze-solving, the solution is the path from the starting point to the exit.

What is the role of knowledge?

The role of knowledge in problem-solving varies based on the complexity and nature of the problem. Knowledge plays a critical role in guiding the problem-solving process. In some problems, extensive domain-specific knowledge is required to recognize patterns, constraints, and possible solutions. For example, chess requires deep knowledge of the game rules and strategic principles to make informed moves. In contrast, other problems may rely more on general problem-solving algorithms and heuristics, requiring less domain-specific knowledge.

Can a computer give the problem solution, or interaction with humans is required?

The level of human interaction required in problem-solving depends on the problem’s complexity and the capabilities of the problem-solving methods being used. In some cases, computers can autonomously find solutions to problems without any interaction with humans. For example, algorithms can efficiently solve mathematical equations or perform certain optimization tasks. However, in more complex and uncertain problems, human interaction may be necessary to provide additional information, preferences, or guidance. Conversational problem-solving, where the computer interacts with users to gather information or provide assistance, can be valuable in addressing such challenges.

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Helenjoy

Research aspirant in deep learning based video compression