[jandrewrogers]

The canonical example is indexing rectangles. They have no total order. It is far from the only example. Any data type where equality and intersection are not equivalent test functions will effectively be non-sortable.

There are many indexing schemes for data with these properties. They focus on topological relationships rather than order relationships.

[AnbeSivam]

Do you know of any blog/papers which talks about this - using topology for such interval data types.