> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/snomed-international-documents/snomed-ct-glossary/i/intensionally-defined-subset.md).

# intensionally defined subset

## intensionally defined subset

A subset whose membership is defined by an intensional subset definition.

An intensional subset definition is defined as

* A subset definition in which the membership is represented by a set of rules specifying the conditions for inclusion.

#### Notes

* The SNOMED CT expression constraint language is the standard way to represent an *intensional subset definition* of a subset of SNOMED CT concepts.
* A row in a Query Specification Reference Set is the standard way to distribute an *intensional subset definition* of a subset of SNOMED CT concepts.

#### Example

* An example of an intensional subset definition is *concepts that are types of respiratory disease characterized by edema*. This is represented as follows in expression constraint language:\
  < [19829001 |disorder of lung|](http://snomed.info/id/19829001) : [116676008 |associated morphology|](http://snomed.info/id/116676008) = [79654002 |edema|](http://snomed.info/id/79654002)

## Related Links

* Intensionally defined subset
* Extensional subset definition
* Extensionally defined subset
* Practical Guide to Reference Sets
* [Wikipedia comparison of extensional and intensional definitions](https://en.wikipedia.org/wiki/Extensional_and_intensional_definitions)

<a href="https://docs.google.com/forms/d/e/1FAIpQLScTmbZIf0UEQwYDkY27EEWBkaiYkHSbR0_9DmFrMLXoQLyL7Q/viewform?usp=pp_url&#x26;entry.1767247133=SNOMED+Glossary&#x26;entry.670899847=intensionally%20defined%20subset" class="button primary">Provide Feedback</a>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.snomed.org/snomed-international-documents/snomed-ct-glossary/i/intensionally-defined-subset.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.