# nnf expression

## NNF expression

**This is a synonym for necessary normal form expression.**

## necessary normal form expression

The necessary normal form expression represents the inferred view of an expression including all the relationships that are necessarily true, with redundancy removed. It is created from the output of the process of classifying the classifiable form expression with a predefined version of SNOMED CT.

The necessary normal form expression represents the relationships used for querying and data analytics over the expression.

#### Notes

* It includes refinements that represent inferred relationships
* It does *not* include any redundant refinements or redundant relationship groups

## Alternatives

* **NNF expression**

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