# Gremlin inference queries in Neptune ML

As described in Neptune ML capabilities, Neptune ML supports training models that can do the following kinds of inference tasks:

**Node classification**– Predicts the categorical feature of a vertex property.**Node regression**– Predicts a numerical property of a vertex.**Edge classification**– Predicts the categorical feature of an edge property.**Edge regression**– Predicts a numerical property of an edge.**Link prediction**– Predicts destination nodes given a source node and outgoing edge, or source nodes given a destination node and incoming edge.

We can illustrate these different tasks with examples that use the MovieLens 100k dataset

**Node classification**: In the dataset above, `Genre`

is a vertex type which is connected to vertex type `Movie`

by edge `included_in`

.
However, if we tweak the dataset to make `Genre`

a categorical`Movie`

, then the problem of inferring `Genre`

for new movies added to our knowledge graph can be solved using node classification
models.

**Node regression**: If we consider the vertex type `Rating`

,
which has properties like `timestamp`

and `score`

, then the problem of inferring
the numerical value `Score`

for a `Rating`

can be solved using node regression models.

**Edge classification**: Similarly, for a `Rated`

edge, if we
have a property `Scale`

that can have one of the values, `Love`

, `Like`

,
`Dislike`

, `Neutral`

, `Hate`

, then the problem of inferring `Scale`

for the `Rated`

edge for new movies/ratings can be solved using edge classification models.

**Edge regression**: Similarly, for the same `Rated`

edge,
if we have a property `Score`

that holds a numerical value for the rating, then this can be
inferred from edge regression models.

**Link prediction**: Problems like, find the top ten users who are most
likely to rate a given movie, or find the top ten Movies that a given user is most likely to rate, falls
under link prediction.

**Topics**

- Neptune ML predicates used in Gremlin inference queries
- Gremlin node classification queries in Neptune ML
- Gremlin node regression queries in Neptune ML
- Gremlin edge classification queries in Neptune ML
- Gremlin edge regression queries in Neptune ML
- Gremlin link prediction queries using link-prediction models in Neptune ML
- List of exceptions for Neptune ML Gremlin inference queries