What we mean by density could you please explain to me with an example what we mean by analysis the density region?

Margin Density Drift Detection methodology signals concept drift by tracking
changes in the expected density distribution of the unlabelled samples with respect to a classification boundary. A classifier’s margin is defined as the region of space close to the model boundary, where the predictions are highly uncertain.

I did not read that paper. But in general density means the number of data points in some part of the space. If some part of the space has many data points then it is said to be dense. If some part of the space do not have many data points, then it is not dense (it is sparse).

A change in density would mean that amount of data points in some part of the space is changing.

Thanxs for your reply.What we mean by Margin density if we analysis the margin density as it is mentioned in the question . If I have the dataset what we mean by margin density