| Task | A Problem that can be assigned. Typically comes with Instructions (guide to Solutions). |
| Problem | A Goal with (all) relevant constraints (≈ requirements). |
| Problem Family | A set of problems that are similar in some (important) ways; a Problem plus variations of that Problem. |
| Goal | A (future) State to be attained, plus optional constraints on the Goal. |
| State | A set of values (with error bounds) for a set of variables relevant to a Goal. |
| Environment | A set of constraints relevant to a Task but not counted as part of a Task proper. |
| World | A set of constraints that a set of Environments have in common. |
| Constraint | A set of factors that limit the flexibility of that which it constrains. |
| Solution | The set of (atomic) actions that can achieve a Goal. |
| Action | The changes an Agent can make to variables relevant to a Task-Environment. |
| Plan | A partial way to accomplish a Task. |
| Instructions | Partial Plan for accomplishing a Task, typically given to an Agent along with a Task by a Teacher. |
| Teacher | The Agent assigning a Task to another Agent (student), optionally in charge of Instructions. |
| Solution Constraint | Reduces the flexibility for producing a Solution. |
| Task Constraint | Limits the allowed Solution Space for a Problem. Can help or hinder a Task to be achieved. |
| Solution Space | The amount of variation allowed on a State while still counting as a Solution to a Problem. |
| Task Space | The size of variations on a Task that would have be explored with no up-front knowledge or information about the Solution Space of a Problem. |
| Task | All tasks have a limited time & energy: No Task exists that can be performed with infinite energy, or for for which infinite time is available for achieving. |
| LTE | Limited Time & Energy. |
| Closed Problem | May be assigned as a Task with known Time & Energy for achieving a solution. |
| Example | Doing the dishes. |
| Plans for Closed problems | Can be reliably produced for closed problems, e.g. in the form of Instructions. |
| Open Problem | A Problem whose solution is unknown and cannot be obviously assumed from analogy with similar problems whose solution is known. Cannot be guaranteed a solution with LTE. |
| Example | Any research problem for which no known solution exists. |
| Plans for Open problems | Cannot be reliably produced. |
2018©K. R. Thórisson
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